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3 commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Song Liu
|
5a897531e0 |
perf bpf_skel: Do not use typedef to avoid error on old clang
When building bpf_skel with clang-10, typedef causes confusions like:
libbpf: map 'prev_readings': unexpected def kind var.
Fix this by removing the typedef.
Fixes:
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Song Liu
|
f7c4e85bcc |
perf bpf: Fix building perf with BUILD_BPF_SKEL=1 by default in more distros
Arnaldo reported that building all his containers with BUILD_BPF_SKEL=1
to then make this the default he found problems in some distros where
the system linux/bpf.h file was being used and lacked this:
util/bpf_skel/bperf_leader.bpf.c:13:20: error: use of undeclared identifier 'BPF_F_PRESERVE_ELEMS'
__uint(map_flags, BPF_F_PRESERVE_ELEMS);
So use instead the vmlinux.h file generated by bpftool from BTF info.
This fixed these as well, getting the build back working on debian:11,
debian:experimental and ubuntu:21.10:
In file included from In file included from util/bpf_skel/bperf_leader.bpf.cutil/bpf_skel/bpf_prog_profiler.bpf.c::33:
:
In file included from In file included from /usr/include/linux/bpf.h/usr/include/linux/bpf.h::1111:
:
/usr/include/linux/types.h/usr/include/linux/types.h::55::1010:: In file included from util/bpf_skel/bperf_follower.bpf.c:3fatal errorfatal error:
: : In file included from /usr/include/linux/bpf.h:'asm/types.h' file not found11'asm/types.h' file not found:
/usr/include/linux/types.h:5:10: fatal error: 'asm/types.h' file not found
#include <asm/types.h>#include <asm/types.h>
^~~~~~~~~~~~~ ^~~~~~~~~~~~~
#include <asm/types.h>
^~~~~~~~~~~~~
1 error generated.
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Song Liu <song@kernel.org>
Tested-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/CF175681-8101-43D1-ABDB-449E644BE986@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Song Liu
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7fac83aaf2 |
perf stat: Introduce 'bperf' to share hardware PMCs with BPF
The perf tool uses performance monitoring counters (PMCs) to monitor system performance. The PMCs are limited hardware resources. For example, Intel CPUs have 3x fixed PMCs and 4x programmable PMCs per cpu. Modern data center systems use these PMCs in many different ways: system level monitoring, (maybe nested) container level monitoring, per process monitoring, profiling (in sample mode), etc. In some cases, there are more active perf_events than available hardware PMCs. To allow all perf_events to have a chance to run, it is necessary to do expensive time multiplexing of events. On the other hand, many monitoring tools count the common metrics (cycles, instructions). It is a waste to have multiple tools create multiple perf_events of "cycles" and occupy multiple PMCs. bperf tries to reduce such wastes by allowing multiple perf_events of "cycles" or "instructions" (at different scopes) to share PMUs. Instead of having each perf-stat session to read its own perf_events, bperf uses BPF programs to read the perf_events and aggregate readings to BPF maps. Then, the perf-stat session(s) reads the values from these BPF maps. Please refer to the comment before the definition of bperf_ops for the description of bperf architecture. bperf is off by default. To enable it, pass --bpf-counters option to perf-stat. bperf uses a BPF hashmap to share information about BPF programs and maps used by bperf. This map is pinned to bpffs. The default path is /sys/fs/bpf/perf_attr_map. The user could change the path with option --bpf-attr-map. Committer testing: # dmesg|grep "Performance Events" -A5 [ 0.225277] Performance Events: Fam17h+ core perfctr, AMD PMU driver. [ 0.225280] ... version: 0 [ 0.225280] ... bit width: 48 [ 0.225281] ... generic registers: 6 [ 0.225281] ... value mask: 0000ffffffffffff [ 0.225281] ... max period: 00007fffffffffff # # for a in $(seq 6) ; do perf stat -a -e cycles,instructions sleep 100000 & done [1] 2436231 [2] 2436232 [3] 2436233 [4] 2436234 [5] 2436235 [6] |