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Smita Koralahalli 86c2bc3da7 perf vendor events amd: Fix broken L2 Cache Hits from L2 HWPF metric 
Commit 08ed77e414 ("perf vendor events amd: Add recommended events")
added the hits event "L2 Cache Hits from L2 HWPF" with the same metric
expression as the accesses event "L2 Cache Accesses from L2 HWPF":

$ perf list --details
...
  l2_cache_accesses_from_l2_hwpf
     [L2 Cache Accesses from L2 HWPF]
     [l2_pf_hit_l2 + l2_pf_miss_l2_hit_l3 + l2_pf_miss_l2_l3]
  l2_cache_hits_from_l2_hwpf
     [L2 Cache Hits from L2 HWPF]
     [l2_pf_hit_l2 + l2_pf_miss_l2_hit_l3 + l2_pf_miss_l2_l3]
...

This was wrong and led to counting hits the same as accesses. Section
2.1.15.2 "Performance Measurement" of "PPR for AMD Family 17h Model 31h
B0 - 55803 Rev 0.54 - Sep 12, 2019", documents the hits event with
EventCode 0x70 which is the same as l2_pf_hit_l2.

Fix this, and massage the description for l2_pf_hit_l2 as the hits event
is now the duplicate of l2_pf_hit_l2. AMD recommends using the recommended
event over other events if the duplicate exists and maintain both for
consistency. Hence, l2_cache_hits_from_l2_hwpf should override
l2_pf_hit_l2.

Before:

 # perf stat -M l2_cache_accesses_from_l2_hwpf,l2_cache_hits_from_l2_hwpf sleep 1

 Performance counter stats for 'sleep 1':

             1,436      l2_pf_miss_l2_l3          # 11114.00 l2_cache_accesses_from_l2_hwpf
                                                  # 11114.00 l2_cache_hits_from_l2_hwpf
             4,482      l2_pf_hit_l2
             5,196      l2_pf_miss_l2_hit_l3

       1.001765339 seconds time elapsed

After:

 # perf stat -M l2_cache_accesses_from_l2_hwpf sleep 1

 Performance counter stats for 'sleep 1':

             1,477      l2_pf_miss_l2_l3          # 10442.00 l2_cache_accesses_from_l2_hwpf
             3,978      l2_pf_hit_l2
             4,987      l2_pf_miss_l2_hit_l3

       1.001491186 seconds time elapsed

 # perf stat -e l2_cache_hits_from_l2_hwpf sleep 1

 Performance counter stats for 'sleep 1':

             3,983      l2_cache_hits_from_l2_hwpf

       1.001329970 seconds time elapsed

Note the difference in performance counter values for the accesses
versus the hits after the fix, and the hits event now counting the same
as l2_pf_hit_l2.

Fixes: 08ed77e414 ("perf vendor events amd: Add recommended events")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Reviewed-by: Robert Richter <rrichter@amd.com>
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Tested-by: Arnaldo Carvalho de Melo <acme@kernel.org> # On a 3900X
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin Liška <mliska@suse.cz>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vijay Thakkar <vijaythakkar@me.com>
Cc: linux-perf-users@vger.kernel.org
Link: https://lore.kernel.org/r/20210406215944.113332-2-Smita.KoralahalliChannabasappa@amd.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-04-08 14:24:38 -03:00
arch Two fixes: 2021-03-28 12:19:16 -07:00
block block: don't create too many partitions 2021-03-27 09:22:18 -06:00
certs certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID 2021-01-21 16:16:10 +00:00
crypto crypto: mips/poly1305 - enable for all MIPS processors 2021-03-08 11:52:17 +01:00
Documentation arm64 fixes for -rc5 2021-03-25 11:07:40 -07:00
drivers A fix for auxdisplay: 2021-03-28 13:20:38 -07:00
fs 5 cifs/smb3 fixes, 2 for stable, includes an important fix for encryption and an ACL fix, as well as a fix for possible reflink data corruption 2021-03-28 12:06:21 -07:00
include Fix the non-debug mutex_lock_io_nested() method to map to mutex_lock_io() instead of mutex_lock(). 2021-03-28 12:12:22 -07:00
init Merge branch 'akpm' (patches from Andrew) 2021-03-14 12:23:34 -07:00
ipc fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
kernel io_uring-5.12-2021-03-27 2021-03-28 11:42:05 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-03-24 18:16:04 -07:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm Merge branch 'akpm' (patches from Andrew) 2021-03-25 11:43:43 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-03-24 18:16:04 -07:00
samples Merge git://git.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2021-03-09 17:15:56 -08:00
scripts kbuild: fix ld-version.sh to not be affected by locale 2021-03-13 11:12:13 +09:00
security integrity-v5.12-fix 2021-03-25 16:46:43 -07:00
sound sound fixes for 5.12-rc4 2021-03-19 09:53:32 -07:00
tools perf vendor events amd: Fix broken L2 Cache Hits from L2 HWPF metric 2021-04-08 14:24:38 -03:00
usr Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
virt KVM: x86/mmu: Consider the hva in mmu_notifier retry 2021-02-22 13:16:53 -05:00
.clang-format cxl for 5.12 2021-02-24 09:38:36 -08:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore clang-lto series for v5.12-rc1 2021-02-23 09:28:51 -08:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2021-03-25 11:43:43 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS treewide: Miguel has moved 2021-02-26 09:41:03 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge remote-tracking branch 'torvalds/master' into perf/core 2021-03-29 10:39:10 -03:00
Makefile Linux 5.12-rc5 2021-03-28 15:48:16 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.