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187230 commits

Author SHA1 Message Date
Ingo Molnar
3b0d516463 perf probe: Fix !dwarf build
Fix the !drawf build.

This uses the existing NO_DWARF_SUPPORT mechanism we use for that,
but it's really fragile and needs a cleanup. (in a separate patch)

1) Such uses:

 #ifndef NO_DWARF_SUPPORT

are double inverted logic a'la 'not not'. Instead the flag should
be called DWARF_SUPPORT.

2) Furthermore, assymetric #ifdef polluted code flow like:

        if (need_dwarf)
 #ifdef NO_DWARF_SUPPORT
                die("Debuginfo-analysis is not supported");
 #else   /* !NO_DWARF_SUPPORT */
                pr_debug("Some probes require debuginfo.\n");

        fd = open_vmlinux();

is very fragile and not acceptable. Instead of that helper functions
should be created and the dwarf/no-dwarf logic should be separated more
cleanly.

3) Local variable #ifdefs like this:

 #ifndef NO_DWARF_SUPPORT
        int fd;
 #endif

Are fragile as well and should be eliminated. Helper functions achieve
that too.

Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220612.32050.33806.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 12:13:28 +01:00
Masami Hiramatsu
7df2f32956 perf probe: Add data structure member access support
Support accessing members in the data structures. With this,
perf-probe accepts data-structure members(IOW, it now accepts
dot '.' and arrow '->' operators) as probe arguemnts.

e.g.

 ./perf probe --add 'schedule:44 rq->curr'

 ./perf probe --add 'vfs_read file->f_op->read file->f_path.dentry'

Note that '>' can be interpreted as redirection in command-line.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220626.32050.57552.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 12:11:15 +01:00
Masami Hiramatsu
fb1587d869 perf probe: List probes with line number and file name
Improve --list to show current exist probes with line number and
file name. This enables user easily to check which line is
already probed.

for example:

 ./perf probe --list
 probe:vfs_read       (on vfs_read:8@linux-2.6-tip/fs/read_write.c)

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220619.32050.48702.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:32:32 +01:00
Masami Hiramatsu
4235b0454e perf probe: Introduce kprobe_trace_event and perf_probe_event
Introduce kprobe_trace_event and perf_probe_event and replace
old probe_point structure with it. probe_point structure is
not enough flexible nor extensible. New data structures
will help implementing further features.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220612.32050.33806.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:32:31 +01:00
Masami Hiramatsu
f4d7da499e perf probe: Add --dry-run option
Add --dry-run option for debugging and testing.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220605.32050.6571.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:32:31 +01:00
Masami Hiramatsu
016f262e4f perf probe: Introduce die_find_child() function
Introduce die_find_child() function to integrate DIE-tree
searching functions.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220558.32050.7905.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:32:31 +01:00
Masami Hiramatsu
95a3e4c4e2 perf probe: Rename some die_get_* functions
Rename die_get_real_subprogram and die_get_inlinefunc to
die_find_real_subprogram and die_find_inlinefunc respectively,
because these functions search its children. After that,
'die_get_' means getting a property of that die, and
'die_find_' means searching DIE-tree to get an appropriate
child die.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220551.32050.36181.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:32:30 +01:00
Masami Hiramatsu
12a1fadb41 perf probe: Rename session to param
Since this name 'session' conflicts with 'perf_session', and
this structure just holds parameters anymore.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220544.32050.8788.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:32:30 +01:00
Masami Hiramatsu
e0faa8d358 perf probe: Move add-probe routine to util/
Move add-probe routine to util/probe_event.c. This simplifies
main routine for reducing maintenance cost.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220537.32050.72214.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:32:30 +01:00
Masami Hiramatsu
31facc5f1a perf probe: Use wrapper functions
Use wrapped functions as much as possible, to check out of
memory conditions in perf probe.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220530.32050.53951.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:32:29 +01:00
Masami Hiramatsu
a1d37d5285 perf tools: Introduce xzalloc() for detecting out of memory conditions
Introducing xzalloc() which wrapping zalloc() for detecting out
of memory conditions.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220521.32050.85155.stgit@localhost6.localdomain6>
[ -v2: small cleanups in surrounding code ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:32:29 +01:00
Ingo Molnar
e4713e93b1 Merge branch 'perf/urgent' into perf/core
Merge reason: We'll be queueing dependent changes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 11:31:48 +01:00
Frederic Weisbecker
a6b84574ee perf: Fix unexported generic perf_arch_fetch_caller_regs
perf_arch_fetch_caller_regs() is exported for the overriden x86
version, but not for the generic weak version.

As a general rule, weak functions should not have their symbol
exported in the same file they are defined.

So let's export it on trace_event_perf.c as it is used by trace
events only.

This fixes:

	ERROR: ".perf_arch_fetch_caller_regs" [fs/xfs/xfs.ko] undefined!
	ERROR: ".perf_arch_fetch_caller_regs" [arch/powerpc/platforms/cell/spufs/spufs.ko] undefined!

-v2: And also only build it if trace events are enabled.
-v3: Fix changelog mistake

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268697902-9518-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 10:44:42 +01:00
Robert Richter
984763cb90 perf, x86: Report error code that returned from x86_pmu.hw_config()
If x86_pmu.hw_config() fails a fixed error code (-EOPNOTSUPP) is
returned even if a different error was reported. This patch fixes
this.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Acked-by: Cyrill Gorcunov <gorcunov@gmail.com>
Acked-by: Lin Ming <ming.m.lin@intel.com>
Cc: acme@redhat.com
Cc: eranian@google.com
Cc: gorcunov@openvz.org
Cc: peterz@infradead.org
Cc: fweisbec@gmail.com
LKML-Reference: <20100316160733.GR1585@erda.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-17 10:43:50 +01:00
Arnaldo Carvalho de Melo
00909e9551 perf top: Add missing initialization to zero
The dso_short_width has to start as zero, as we're calculating
the maximum short DSO name length, somehow I missed this one.

Reported-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268774926-27488-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-16 22:51:00 +01:00
Masami Hiramatsu
5cc718b9da kprobes: Hide CONFIG_OPTPROBES and set if arch supports optimized kprobes
Hide CONFIG_OPTPROBES and set if the arch supports optimized
kprobes (IOW, HAVE_OPTPROBES=y), since this option doesn't
change the major behavior of kprobes, and workarounds for minor
changes are documented.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Dieter Ries <mail@dieterries.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100315170054.31593.3153.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-16 11:07:23 +01:00
Masami Hiramatsu
d0cb4260f8 perf probe: Use original address instead of CU-based address
Use original address for looking up the location of variables
for dwarf_getlocation_addr() instead of CU-based address.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20100315170235.31852.91195.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-16 10:02:19 +01:00
Masami Hiramatsu
67c7ff7c56 perf probe: Fix offset to allow signed value
Fix dereference offset to intmax_t from uintmax_t, because
it can have negative values (for example local variable's offset
from frame pointer).

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20100315170228.31852.71946.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-16 10:02:18 +01:00
Arnaldo Carvalho de Melo
b63be8d7be perf top: Improve the autosizing of column lenghts
When profiling C++ workloads the symbol name length can be
really big, so cap it before it garbles the result.

This builds upon the autosizing already present where we choose
to use the short, basename of DSOs instead of its long, full
pathname.

Reported-by: Pavel Krauz <krauz@cngroup.cz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268676230-9261-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-16 09:52:36 +01:00
Lin Ming
8ea7f54410 x86, perf: Fix comments in Pentium-4 PMU definitions
Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1268705556.3379.8.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-16 09:37:46 +01:00
Frederic Weisbecker
1d199b1ad6 perf: Fix unexported generic perf_arch_fetch_caller_regs
perf_arch_fetch_caller_regs() is exported for the overriden x86
version, but not for the generic weak version.

As a general rule, weak functions should not have their symbol
exported in the same file they are defined.

So let's export it on trace_event_perf.c as it is used by trace
events only.

This fixes:

	ERROR: ".perf_arch_fetch_caller_regs" [fs/xfs/xfs.ko] undefined!
	ERROR: ".perf_arch_fetch_caller_regs" [arch/powerpc/platforms/cell/spufs/spufs.ko] undefined!

-v2: And also only build it if trace events are enabled.
-v3: Fix changelog mistake

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268697902-9518-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-16 09:27:27 +01:00
Arnaldo Carvalho de Melo
d06d92b7c9 perf annotate: Properly notify the user that vmlinux is missing
Before this patch we would not find a vmlinux, then try to pass
objdump "[kernel.kallsyms]" as the filename, it would get
confused and produce no output:

 [root@doppio ~]# perf annotate n_tty_write

 ------------------------------------------------
  Percent |      Source code & Disassembly of [kernel.kallsyms]
 ------------------------------------------------

Now we check that and emit meaningful warning:

 [root@doppio ~]# perf annotate n_tty_write
 Can't annotate n_tty_write: No vmlinux file was found in the
 path: [0] vmlinux
 [1] /boot/vmlinux
 [2] /boot/vmlinux-2.6.34-rc1-tip+
 [3] /lib/modules/2.6.34-rc1-tip+/build/vmlinux
 [4] /usr/lib/debug/lib/modules/2.6.34-rc1-tip+/vmlinux
 [root@doppio ~]#

This bug was introduced when we added automatic search for
vmlinux, before that time the user had to specify a vmlinux
file.

v2: Print the warning just for the first symbol found when no
    symbol name is specified, otherwise it will spam the screen
    repeating the warning for each symbol.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: <stable@kernel.org>
LKML-Reference: <1268669073-6856-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-15 17:16:25 +01:00
Arnaldo Carvalho de Melo
b0a9ab62ab perf top: Properly notify the user that vmlinux is missing
Before this patch this message would very briefly appear on the
screen and then the screen would get updates only on the top,
for number of interrupts received, etc, but no annotation would
be performed:

 [root@doppio linux-2.6-tip]# perf top -s n_tty_write > /tmp/bla
 objdump: '[kernel.kallsyms]': No such file

Now this is what the user gets:

 [root@doppio linux-2.6-tip]# perf top -s n_tty_write
 Can't annotate n_tty_write: No vmlinux file was found in the
 path: [0] vmlinux
 [1] /boot/vmlinux
 [2] /boot/vmlinux-2.6.33-rc5
 [3] /lib/modules/2.6.33-rc5/build/vmlinux
 [4] /usr/lib/debug/lib/modules/2.6.33-rc5/vmlinux
 [root@doppio linux-2.6-tip]#

This bug was introduced when we added automatic search for
vmlinux, before that time the user had to specify a vmlinux
file.

Reported-by: David S. Miller <davem@davemloft.net>
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: <stable@kernel.org>
LKML-Reference: <1268664418-28328-2-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-15 16:08:42 +01:00
Eric B Munson
bedbfdea31 perf record: Enable the enable_on_exec flag if record forks the target
When forking its target, perf record can capture data from
before the target application is started.  Perf stat uses the
enable_on_exec flag in the event attributes to keep from
displaying events from before the target program starts, this
patch adds the same functionality to perf record when it is will
fork the target process.

Signed-off-by: Eric B Munson <ebmunson@us.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1268664418-28328-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-15 16:08:22 +01:00
Cyrill Gorcunov
e449526282 perf, x86: Enable not tagged retired instruction counting on P4s
This should turn on instruction counting on P4s, which was missing in
the first version of the new PMU driver.

It's inaccurate for now, we still need dependant event to tag mops
before we can count them precisely. The result is that the number of
instruction may be lifted up.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1268629102.3355.11.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-15 08:14:34 +01:00
Cyrill Gorcunov
8576e19716 x86, perf: Unmask LVTPC only if we have APIC supported
Ingo reported:

 |
 | There's a build failure on -tip with the P4 driver, on UP 32-bit, if
 | PERF_EVENTS is enabled but UP_APIC is disabled:
 |
 | arch/x86/built-in.o: In function `p4_pmu_handle_irq':
 | perf_event.c:(.text+0xa756): undefined reference to `apic'
 | perf_event.c:(.text+0xa76e): undefined reference to `apic'
 |

So we have to unmask LVTPC only if we're configured to have one.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Lin Ming <ming.m.lin@intel.com>
CC: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20100313081116.GA5179@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-13 13:32:27 +01:00
Masami Hiramatsu
fc6ceea045 perf probe: Fix need_dwarf flag if lazy matching is used
Set need_dwarf if lazy matching pattern is specified, because
lazy matching requires real source path for which we must use
debuginfo.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20100312232224.2017.54550.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-13 08:32:22 +01:00
Masami Hiramatsu
594087a04e perf probe: Fix probe_point buffer overrun
Fix probe_point array-size overrun problem. In some cases (e.g.
inline function), one user-specified probe-point can be
translated to many probe address, and it overruns pre-defined
array-size. This also removes redundant MAX_PROBES macro
definition.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: <stable@kernel.org>
LKML-Reference: <20100312232217.2017.45017.stgit@localhost6.localdomain6>
[ Note that only root can create new probes. Eventually we should remove
  the MAX_PROBES limit, but that is a larger patch not eligible to
  perf/urgent treatment. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-13 08:32:22 +01:00
Arnaldo Carvalho de Melo
567e54790e perf tools: Fix non-newt build
The use_browser needs to be in a file that is always built and
also we need a browser__show_help stub in that case.

Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268438710-32697-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-13 08:23:37 +01:00
Ingo Molnar
0308635917 Merge branch 'perf/x86' into perf/core
Merge reason: The new P4 driver is stable and ready now for more
              testing.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 21:06:37 +01:00
Arnaldo Carvalho de Melo
3997d3776a perf hist: Don't fprintf the callgraph unconditionally
[root@doppio ~]# perf report -i newt.data | head -10
  # Samples: 11999679868
  #
  # Overhead  Command                  Shared Object  Symbol
  # ........  .......  .............................  ......
  #
      63.61%     perf  libslang.so.2.1.4              [.] SLsmg_write_chars
       6.30%     perf  perf                           [.] symbols__find
       2.19%     perf  libnewt.so.0.52.10             [.] newtListboxAppendEntry
       2.08%     perf  libslang.so.2.1.4              [.] SLsmg_write_chars@plt
       1.99%     perf  libc-2.10.2.so                 [.] _IO_vfprintf_internal
  [root@doppio ~]#

Not good, the newt form for report works, but slang has to eat
the cost of the additional callgraph lines everytime it prints a
line, and the callgraph doesn't appear on the screen, so move
the callgraph printing to a separate function and don't use it
in newt.c.

Newt tree widgets are being investigated to properly support
callgraphs, but till that gets merged, lets remove this huge
overhead and show at least the symbol overheads for a callgraph
rich perf.data with good performance.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268408808-13595-2-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 20:31:53 +01:00
Arnaldo Carvalho de Melo
cb7afb7092 perf newt: Use newtGetScreenSize
For consistency, use the newt API more fully.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268408808-13595-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 20:31:53 +01:00
Arnaldo Carvalho de Melo
7081e087b9 perf newt: Add 'Q', 'q' and Ctrl+C as ways to exit from forms
These are keys people expect when pressed to exit the current
widget, so have associate all of them to this semantic.

Suggested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268401692-9361-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 20:31:52 +01:00
Arnaldo Carvalho de Melo
f9224c5c94 perf report: Implement initial UI using newt
Newt has widespread availability and provides a rather simple
API as can be seen by the size of this patch.

The work needed to support it will benefit other frontends too.

In this initial patch it just checks if the output is a tty, if
not it falls back to the previous behaviour, also if
newt-devel/libnewt-dev is not installed the previous behaviour
is maintaned.

Pressing enter on a symbol will annotate it, ESC in the
annotation window will return to the report symbol list.

More work will be done to remove the special casing in
color_fprintf, stop using fmemopen/FILE in the printing of
hist_entries, etc.

Also the annotation doesn't need to be done via spawning "perf
annotate" and then browsing its output, we can do better by
calling directly the builtin-annotate.c functions, that would
then be moved to tools/perf/util/annotate.c and shared with perf
top, etc

But lets go by baby steps, this patch already improves perf
usability by allowing to quickly do annotations on symbols from
the report screen and provides a first experimentation with
libnewt/TUI integration of tools.

Tested on RHEL5 and Fedora12 X86_64 and on Debian PARISC64 to
browse a perf.data file collected on a Fedora12 x86_64 box.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268349164-5822-5-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 10:28:46 +01:00
Arnaldo Carvalho de Melo
dd2ee78dd8 perf tools: Add missing bytes printed in hist_entry__fprintf
We need those to properly size the browser widht in the newt
TUI.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268349164-5822-4-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 10:28:37 +01:00
Arnaldo Carvalho de Melo
b4f5296f0e perf tools: Use eprintf for pr_{err,warning,info} too
Just like we do for pr_debug, so that we can have a single point
where to redirect to the currently used output system, be it
stdio or newt.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268349164-5822-3-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 10:28:36 +01:00
Arnaldo Carvalho de Melo
895f0edc3c perf top: Export get_window_dimensions
Will be used by the newt code too.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268349164-5822-2-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 10:28:36 +01:00
Arnaldo Carvalho de Melo
fe2197b8bb perf symbols: Bump plt synthesizing warning debug level
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268349164-5822-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 10:28:36 +01:00
Ingo Molnar
937779db13 Merge branch 'perf/urgent' into perf/core
Merge reason: We want to queue up a dependent patch.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 10:20:59 +01:00
Cyrill Gorcunov
0b861225a5 x86, perf: Fix NULL deref on not assigned x86_pmu
In case of not assigned x86_pmu and software events NULL dereference may
being hit via x86_pmu::schedule_events method.

Fix it by checking if x86_pmu is initialized at all.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20100311215016.GG25162@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-12 10:18:42 +01:00
Arnaldo Carvalho de Melo
6230f2c7ef perf record: Mention paranoid sysctl when failing to create counter
[acme@mica linux-2.6-tip]$ perf record -a -f
   Fatal: Permission error - are you root?
 	 Consider tweaking /proc/sys/kernel/perf_event_paranoid.

 [acme@mica linux-2.6-tip]$

Suggested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1268333592-30872-2-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 20:00:48 +01:00
Arnaldo Carvalho de Melo
9f591fd76a perf record: Don't try to find buildids in a zero sized file
Fixing this symptom:

 [acme@mica linux-2.6-tip]$ perf record -a -f
   Fatal: Permission error - are you root?

 Bus error
 [acme@mica linux-2.6-tip]$

I.e. if for some reason no data is collected, in this case a non
root user trying to do systemwide profiling, no data will be
collected, and then we end up trying to mmap a zero sized file
and access the file header, b00m.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: <stable@kernel.org>
LKML-Reference: <1268333592-30872-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 20:00:32 +01:00
Cyrill Gorcunov
a072738e04 perf, x86: Implement initial P4 PMU driver
The netburst PMU is way different from the "architectural
perfomance monitoring" specification that current CPUs use.
P4 uses a tuple of ESCR+CCCR+COUNTER MSR registers to handle
perfomance monitoring events.

A few implementational details:

1) We need a separate x86_pmu::hw_config helper in struct
   x86_pmu since register bit-fields are quite different from P6,
   Core and later cpu series.

2) For the same reason is a x86_pmu::schedule_events helper
   introduced.

3) hw_perf_event::config consists of packed ESCR+CCCR values.
   It's allowed since in reality both registers only use a half
   of their size. Of course before making a real write into a
   particular MSR we need to unpack the value and extend it to
   a proper size.

4) The tuple of packed ESCR+CCCR in hw_perf_event::config
   doesn't describe the memory address of ESCR MSR register
   so that we need to keep a mapping between these tuples
   used and available ESCR (various P4 events may use same
   ESCRs but not simultaneously), for this sake every active
   event has a per-cpu map of hw_perf_event::idx <--> ESCR
   addresses.

5) Since hw_perf_event::idx is an offset to counter/control register
   we need to lift X86_PMC_MAX_GENERIC up, otherwise kernel
   strips it down to 8 registers and event armed may never be turned
   off (ie the bit in active_mask is set but the loop never reaches
   this index to check), thanks to Peter Zijlstra

Restrictions:

 - No cascaded counters support (do we ever need them?)
 - No dependent events support (so PERF_COUNT_HW_INSTRUCTIONS
   doesn't work for now)
 - There are events with same counters which can't work simultaneously
   (need to use intersected ones due to broken counter 1)
 - No PERF_COUNT_HW_CACHE_ events yet

Todo:

 - Implement dependent events
 - Need proper hashing for event opcodes (no linear search, good for
   debugging stage but not in real loads)
 - Some events counted during a clock cycle -- need to set threshold
   for them and count every clock cycle just to get summary statistics
   (ie to behave the same way as other PMUs do)
 - Need to swicth to use event_constraints
 - To support RAW events we need to encode a global list of P4 events
   into p4_templates
 - Cache events need to be added

Event support status matrix:

 Event			status
 -----------------------------
 cycles			works
 cache-references	works
 cache-misses		works
 branch-misses		works
 bus-cycles		partially (does not work on 64bit cpu with HT enabled)
 instruction		doesnt work (needs dependent event [mop tagging])
 branches		doesnt work

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100311165439.GB5129@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 18:51:08 +01:00
eranian@google.com
9b33fa6ba0 perf_events: Improve task_sched_in()
This patch is an optimization in perf_event_task_sched_in() to avoid
scheduling the events twice in a row.

Without it, the perf_disable()/perf_enable() pair is invoked twice,
thereby pinned events counts while scheduling flexible events and we go
throuh hw_perf_enable() twice.

By encapsulating, the whole sequence into perf_disable()/perf_enable() we
ensure, hw_perf_enable() is going to be invoked only once because of the
refcount protection.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268288765-5326-1-git-send-email-eranian@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 15:23:28 +01:00
Xiao Guangrong
639fe4b12f perf: export perf_trace_regs and perf_arch_fetch_caller_regs
Export perf_trace_regs and perf_arch_fetch_caller_regs since module will
use these.

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
[ use EXPORT_PER_CPU_SYMBOL_GPL() ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4B989C1B.2090407@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 15:21:29 +01:00
Peter Zijlstra
45e16a6834 perf, x86: Fix hw_perf_enable() event assignment
What happens is that we schedule badly like:

<...>-1987  [019]   280.252808: x86_pmu_start: event-46/1300c0: idx: 0
<...>-1987  [019]   280.252811: x86_pmu_start: event-47/1300c0: idx: 1
<...>-1987  [019]   280.252812: x86_pmu_start: event-48/1300c0: idx: 2
<...>-1987  [019]   280.252813: x86_pmu_start: event-49/1300c0: idx: 3
<...>-1987  [019]   280.252814: x86_pmu_start: event-50/1300c0: idx: 32
<...>-1987  [019]   280.252825: x86_pmu_stop: event-46/1300c0: idx: 0
<...>-1987  [019]   280.252826: x86_pmu_stop: event-47/1300c0: idx: 1
<...>-1987  [019]   280.252827: x86_pmu_stop: event-48/1300c0: idx: 2
<...>-1987  [019]   280.252828: x86_pmu_stop: event-49/1300c0: idx: 3
<...>-1987  [019]   280.252829: x86_pmu_stop: event-50/1300c0: idx: 32
<...>-1987  [019]   280.252834: x86_pmu_start: event-47/1300c0: idx: 1
<...>-1987  [019]   280.252834: x86_pmu_start: event-48/1300c0: idx: 2
<...>-1987  [019]   280.252835: x86_pmu_start: event-49/1300c0: idx: 3
<...>-1987  [019]   280.252836: x86_pmu_start: event-50/1300c0: idx: 32
<...>-1987  [019]   280.252837: x86_pmu_start: event-51/1300c0: idx: 32 *FAIL*

This happens because we only iterate the n_running events in the first
pass, and reset their index to -1 if they don't match to force a
re-assignment.

Now, in our RR example, n_running == 0 because we fully unscheduled, so
event-50 will retain its idx==32, even though in scheduling it will have
gotten idx=0, and we don't trigger the re-assign path.

The easiest way to fix this is the below patch, which simply validates
the full assignment in the second pass.

Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268311069.5037.31.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 15:21:28 +01:00
Peter Zijlstra
85cfabbcd1 perf, ppc: Fix compile error due to new cpu notifiers
Fix:

  arch/powerpc/kernel/perf_event.c:1334: error: 'power_pmu_notifier' undeclared (first use in this function)
  arch/powerpc/kernel/perf_event.c:1334: error: (Each undeclared identifier is reported only once
  arch/powerpc/kernel/perf_event.c:1334: error: for each function it appears in.)
  arch/powerpc/kernel/perf_event.c:1334: error: implicit declaration of function 'power_pmu_notifier'
  arch/powerpc/kernel/perf_event.c:1334: error: implicit declaration of function 'register_cpu_notifier'

Due to commit 3f6da390 (perf: Rework and fix the arch CPU-hotplug hooks).

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 15:21:27 +01:00
John Kacur
7ae5f21361 perf: Make the install relative to DESTDIR if specified
Without this change, the install path is relative to
prefix/DESTDIR where prefix is automatically set to $HOME.

This can produce unexpected results. For example:

  make -C tools/perf DESTDIR=/home/jkacur/tmp install-man

creates the directory:		/home/jkacur/home/jkacur/tmp/share/...
instead of the expected:	/home/jkacur/tmp/share/...

Signed-off-by: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Kyle McMartin <kyle@redhat.com>
Cc: <stable@kernel.org>
LKML-Reference: <1268312220-12880-1-git-send-email-jkacur@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 14:08:11 +01:00
Masami Hiramatsu
83ff56f46a kprobes: Calculate the index correctly when freeing the out-of-line execution slot
From : Ananth N Mavinakayanahalli <ananth@in.ibm.com>

When freeing the instruction slot, the arithmetic to calculate
the index of the slot in the page needs to account for the total
size of the instruction on the various architectures.

Calculate the index correctly when freeing the out-of-line
execution slot.

Reported-by: Sachin Sant <sachinp@in.ibm.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <4B9667AB.9050507@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 14:06:16 +01:00
Paul Mackerras
a12b51c478 perf tools: Fix sparse CPU numbering related bugs
At present, the perf subcommands that do system-wide monitoring
(perf stat, perf record and perf top) don't work properly unless
the online cpus are numbered 0, 1, ..., N-1.  These tools ask
for the number of online cpus with sysconf(_SC_NPROCESSORS_ONLN)
and then try to create events for cpus 0, 1, ..., N-1.

This creates problems for systems where the online cpus are
numbered sparsely.  For example, a POWER6 system in
single-threaded mode (i.e. only running 1 hardware thread per
core) will have only even-numbered cpus online.

This fixes the problem by reading the /sys/devices/system/cpu/online
file to find out which cpus are online.  The code that does that is in
tools/perf/util/cpumap.[ch], and consists of a read_cpu_map()
function that sets up a cpumap[] array and returns the number of
online cpus.  If /sys/devices/system/cpu/online can't be read or
can't be parsed successfully, it falls back to using sysconf to
ask how many cpus are online and sets up an identity map in cpumap[].

The perf record, perf stat and perf top code then calls
read_cpu_map() in the system-wide monitoring case (instead of
sysconf) and uses cpumap[] to get the cpu numbers to pass to
perf_event_open.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
LKML-Reference: <20100310093609.GA3959@brick.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 13:36:53 +01:00