The commit 94dbfd6781 ("perf parse-events: Architecture specific
leader override") introduced a feature to reorder the slots event to
fulfill the restriction of the perf metrics topdown group. But the
feature doesn't work on the hybrid machine.
$ perf stat -e "{cpu_core/instructions/,cpu_core/slots/,cpu_core/topdown-retiring/}" -a sleep 1
Performance counter stats for 'system wide':
<not counted> cpu_core/instructions/
<not counted> cpu_core/slots/
<not supported> cpu_core/topdown-retiring/
1.002871801 seconds time elapsed
A hybrid platform has a different PMU name for the core PMUs, while
current perf hard code the PMU name "cpu".
Introduce a new function to check whether the system supports the perf
metrics feature. The result is cached for the future usage.
For X86, the core PMU name always has "cpu" prefix.
With the patch:
$ perf stat -e "{cpu_core/instructions/,cpu_core/slots/,cpu_core/topdown-retiring/}" -a sleep 1
Performance counter stats for 'system wide':
76,337,010 cpu_core/slots/
10,416,809 cpu_core/instructions/
11,692,372 cpu_core/topdown-retiring/
1.002805453 seconds time elapsed
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20220518143900.1493980-5-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The evsel->name may have a different format for a topdown event, a pure
topdown name (e.g., topdown-fe-bound), or a PMU name + a topdown name
(e.g., cpu/topdown-fe-bound/). The cpu/topdown-fe-bound/ kind format
isn't supported by the arch_evlist__leader(). This format is a very
common format for a hybrid platform, which requires specifying the PMU
name for each event.
Without the patch,
$ perf stat -e '{instructions,slots,cpu/topdown-fe-bound/}' -a sleep 1
Performance counter stats for 'system wide':
<not counted> instructions
<not counted> slots
<not supported> cpu/topdown-fe-bound/
1.003482041 seconds time elapsed
Some events weren't counted. Try disabling the NMI watchdog:
echo 0 > /proc/sys/kernel/nmi_watchdog
perf stat ...
echo 1 > /proc/sys/kernel/nmi_watchdog
The events in group usually have to be from the same PMU. Try reorganizing the group.
With the patch,
$ perf stat -e '{instructions,slots,cpu/topdown-fe-bound/}' -a sleep 1
Performance counter stats for 'system wide':
157,383,996 slots
25,011,711 instructions
27,441,686 cpu/topdown-fe-bound/
1.003530890 seconds time elapsed
Fixes: bc355822f0 ("perf parse-events: Move slots only with topdown")
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20220518143900.1493980-4-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If any member in a group has a different cpu mask than the other
members, the current perf stat disables group. when the perf metrics
topdown events are part of the group, the below <not supported> error
will be triggered.
$ perf stat -e "{slots,topdown-retiring,uncore_imc_free_running_0/dclk/}" -a sleep 1
WARNING: grouped events cpus do not match, disabling group:
anon group { slots, topdown-retiring, uncore_imc_free_running_0/dclk/ }
Performance counter stats for 'system wide':
141,465,174 slots
<not supported> topdown-retiring
1,605,330,334 uncore_imc_free_running_0/dclk/
The perf metrics topdown events must always be grouped with a slots
event as leader.
Factor out evsel__remove_from_group() to only remove the regular events
from the group.
Remove evsel__must_be_in_group(), since no one use it anymore.
With the patch, the topdown events aren't broken from the group for the
splitting.
$ perf stat -e "{slots,topdown-retiring,uncore_imc_free_running_0/dclk/}" -a sleep 1
WARNING: grouped events cpus do not match, disabling group:
anon group { slots, topdown-retiring, uncore_imc_free_running_0/dclk/ }
Performance counter stats for 'system wide':
346,110,588 slots
124,608,256 topdown-retiring
1,606,869,976 uncore_imc_free_running_0/dclk/
1.003877592 seconds time elapsed
Fixes: a9a1790247 ("perf stat: Ensure group is defined on top of the same cpu mask")
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20220518143900.1493980-3-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The patch ("perf evlist: Keep topdown counters in weak group") fixes the
perf metrics topdown event issue when the topdown events are in a weak
group on a non-hybrid platform. However, it doesn't work for the hybrid
platform.
$./perf stat -e '{cpu_core/slots/,cpu_core/topdown-bad-spec/,
cpu_core/topdown-be-bound/,cpu_core/topdown-fe-bound/,
cpu_core/topdown-retiring/,cpu_core/branch-instructions/,
cpu_core/branch-misses/,cpu_core/bus-cycles/,cpu_core/cache-misses/,
cpu_core/cache-references/,cpu_core/cpu-cycles/,cpu_core/instructions/,
cpu_core/mem-loads/,cpu_core/mem-stores/,cpu_core/ref-cycles/,
cpu_core/cache-misses/,cpu_core/cache-references/}:W' -a sleep 1
Performance counter stats for 'system wide':
751,765,068 cpu_core/slots/ (84.07%)
<not supported> cpu_core/topdown-bad-spec/
<not supported> cpu_core/topdown-be-bound/
<not supported> cpu_core/topdown-fe-bound/
<not supported> cpu_core/topdown-retiring/
12,398,197 cpu_core/branch-instructions/ (84.07%)
1,054,218 cpu_core/branch-misses/ (84.24%)
539,764,637 cpu_core/bus-cycles/ (84.64%)
14,683 cpu_core/cache-misses/ (84.87%)
7,277,809 cpu_core/cache-references/ (77.30%)
222,299,439 cpu_core/cpu-cycles/ (77.28%)
63,661,714 cpu_core/instructions/ (84.85%)
0 cpu_core/mem-loads/ (77.29%)
12,271,725 cpu_core/mem-stores/ (77.30%)
542,241,102 cpu_core/ref-cycles/ (84.85%)
8,854 cpu_core/cache-misses/ (76.71%)
7,179,013 cpu_core/cache-references/ (76.31%)
1.003245250 seconds time elapsed
A hybrid platform has a different PMU name for the core PMUs, while
the current perf hard code the PMU name "cpu".
The evsel->pmu_name can be used to replace the "cpu" to fix the issue.
For a hybrid platform, the pmu_name must be non-NULL. Because there are
at least two core PMUs. The PMU has to be specified.
For a non-hybrid platform, the pmu_name may be NULL. Because there is
only one core PMU, "cpu". For a NULL pmu_name, we can safely assume that
it is a "cpu" PMU.
In case other PMUs also define the "slots" event, checking the PMU type
as well.
With the patch,
$ perf stat -e '{cpu_core/slots/,cpu_core/topdown-bad-spec/,
cpu_core/topdown-be-bound/,cpu_core/topdown-fe-bound/,
cpu_core/topdown-retiring/,cpu_core/branch-instructions/,
cpu_core/branch-misses/,cpu_core/bus-cycles/,cpu_core/cache-misses/,
cpu_core/cache-references/,cpu_core/cpu-cycles/,cpu_core/instructions/,
cpu_core/mem-loads/,cpu_core/mem-stores/,cpu_core/ref-cycles/,
cpu_core/cache-misses/,cpu_core/cache-references/}:W' -a sleep 1
Performance counter stats for 'system wide':
766,620,266 cpu_core/slots/ (84.06%)
73,172,129 cpu_core/topdown-bad-spec/ # 9.5% bad speculation (84.06%)
193,443,341 cpu_core/topdown-be-bound/ # 25.0% backend bound (84.06%)
403,940,929 cpu_core/topdown-fe-bound/ # 52.3% frontend bound (84.06%)
102,070,237 cpu_core/topdown-retiring/ # 13.2% retiring (84.06%)
12,364,429 cpu_core/branch-instructions/ (84.03%)
1,080,124 cpu_core/branch-misses/ (84.24%)
564,120,383 cpu_core/bus-cycles/ (84.65%)
36,979 cpu_core/cache-misses/ (84.86%)
7,298,094 cpu_core/cache-references/ (77.30%)
227,174,372 cpu_core/cpu-cycles/ (77.31%)
63,886,523 cpu_core/instructions/ (84.87%)
0 cpu_core/mem-loads/ (77.31%)
12,208,782 cpu_core/mem-stores/ (77.31%)
566,409,738 cpu_core/ref-cycles/ (84.87%)
23,118 cpu_core/cache-misses/ (76.71%)
7,212,602 cpu_core/cache-references/ (76.29%)
1.003228667 seconds time elapsed
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20220518143900.1493980-2-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Avi Kivity reported a problem where the __weak
btf__load_from_kernel_by_id() in tools/perf/util/bpf-event.c was being
used and it called btf__get_from_id() in tools/lib/bpf/btf.c that in
turn called back to btf__load_from_kernel_by_id(), resulting in an
endless loop.
Fix this by adding a feature test to check if
btf__load_from_kernel_by_id() is available when building perf with
LIBBPF_DYNAMIC=1, and if not then provide the fallback to the old
btf__get_from_id(), that doesn't call back to btf__load_from_kernel_by_id()
since at that time it didn't exist at all.
Tested on Fedora 35 where we have libbpf-devel 0.4.0 with LIBBPF_DYNAMIC
where we don't have btf__load_from_kernel_by_id() and thus its feature
test fail, not defining HAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID:
$ cat /tmp/build/perf-urgent/feature/test-libbpf-btf__load_from_kernel_by_id.make.output
test-libbpf-btf__load_from_kernel_by_id.c: In function ‘main’:
test-libbpf-btf__load_from_kernel_by_id.c:6:16: error: implicit declaration of function ‘btf__load_from_kernel_by_id’ [-Werror=implicit-function-declaration]
6 | return btf__load_from_kernel_by_id(20151128, NULL);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
$
$ nm /tmp/build/perf-urgent/perf | grep btf__load_from_kernel_by_id
00000000005ba180 T btf__load_from_kernel_by_id
$
$ objdump --disassemble=btf__load_from_kernel_by_id -S /tmp/build/perf-urgent/perf
/tmp/build/perf-urgent/perf: file format elf64-x86-64
<SNIP>
00000000005ba180 <btf__load_from_kernel_by_id>:
#include "record.h"
#include "util/synthetic-events.h"
#ifndef HAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID
struct btf *btf__load_from_kernel_by_id(__u32 id)
{
5ba180: 55 push %rbp
5ba181: 48 89 e5 mov %rsp,%rbp
5ba184: 48 83 ec 10 sub $0x10,%rsp
5ba188: 64 48 8b 04 25 28 00 mov %fs:0x28,%rax
5ba18f: 00 00
5ba191: 48 89 45 f8 mov %rax,-0x8(%rbp)
5ba195: 31 c0 xor %eax,%eax
struct btf *btf;
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
int err = btf__get_from_id(id, &btf);
5ba197: 48 8d 75 f0 lea -0x10(%rbp),%rsi
5ba19b: e8 a0 57 e5 ff call 40f940 <btf__get_from_id@plt>
5ba1a0: 89 c2 mov %eax,%edx
#pragma GCC diagnostic pop
return err ? ERR_PTR(err) : btf;
5ba1a2: 48 98 cltq
5ba1a4: 85 d2 test %edx,%edx
5ba1a6: 48 0f 44 45 f0 cmove -0x10(%rbp),%rax
}
<SNIP>
Fixes: 218e7b775d ("perf bpf: Provide a weak btf__load_from_kernel_by_id() for older libbpf versions")
Reported-by: Avi Kivity <avi@scylladb.com>
Link: https://lore.kernel.org/linux-perf-users/f0add43b-3de5-20c5-22c4-70aff4af959f@scylladb.com
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/linux-perf-users/YobjjFOblY4Xvwo7@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It can be convenient to put a string value into a ptwrite payload as
a quick and easy way to identify what is being printed.
To make that useful, if the Intel ptwrite payload value contains only
printable ASCII characters padded with NULLs, then print it also as a
string.
Using the example program from the "Emulated PTWRITE" section of
tools/perf/Documentation/perf-intel-pt.txt:
$ echo -n "Hello" | od -t x8
0000000 0000006f6c6c6548
0000005
$ perf record -e intel_pt//u ./eg_ptw 0x0000006f6c6c6548
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.016 MB perf.data ]
$ perf script --itrace=ew intel-pt-events.py
Intel PT Branch Trace, Power Events, Event Trace and PTWRITE
Switch In 38524/38524 [001] 24166.044995916 0/0
eg_ptw 38524/38524 [001] 24166.045380004 ptwrite jmp IP: 0 payload: 0x6f6c6c6548 Hello 56532c7ce196 perf_emulate_ptwrite+0x16 (/home/ahunter/git/work/eg_ptw)
End
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220509152400.376613-4-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It can be convenient to put a string value into a ptwrite payload as
a quick and easy way to identify what is being printed.
To make that useful, if the Intel ptwrite payload value contains only
printable ASCII characters padded with NULLs, then print it also as a
string.
Using the example program from the "Emulated PTWRITE" section of
tools/perf/Documentation/perf-intel-pt.txt:
$ echo -n "Hello" | od -t x8
0000000 0000006f6c6c6548
0000005
$ perf record -e intel_pt//u ./eg_ptw 0x0000006f6c6c6548
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.016 MB perf.data ]
$ perf script --itrace=ew
eg_ptw 35563 [005] 18256.087338: ptwrite: IP: 0 payload: 0x6f6c6c6548 Hello 55e764db5196 perf_emulate_ptwrite+0x16 (/home/user/eg_ptw)
$
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220509152400.376613-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
ptwrite is an Intel x86 instruction that writes arbitrary values into an
Intel PT trace. It is not supported on all hardware, so provide an
alternative that makes use of TNT packets to convey the payload data.
TNT packets encode Taken/Not-taken conditional branch information, so
taking branches based on the payload value will encode the value into
the TNT packet. Refer to the changes to the documentation file
perf-intel-pt.txt in this patch for an example.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220509152400.376613-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This fixes the issue where the build will fail if only the Python2
runtime is installed but the Python3 devtools are installed. Currently
the workaround is 'make PYTHON=python3'.
Fix it by autodetecting Python based on whether python[x]-config exists
rather than just python[x] because both are needed for the build. Then
-config is stripped to find the Python runtime.
Testing
=======
* Auto detect links with Python3 when the v3 devtools are installed
and only Python 2 runtime is installed
* Auto detect links with Python2 when both devtools are installed
* Sensible warning is printed if no Python devtools are installed
* 'make PYTHON=x' still automatically sets PYTHON_CONFIG=x-config
* 'make PYTHON=x' fails if x-config doesn't exist
* 'make PYTHON=python3' overrides Python2 devtools
* 'make PYTHON=python2' overrides Python3 devtools
* 'make PYTHON_CONFIG=x-config' works
* 'make PYTHON=x PYTHON_CONFIG=x' works
* 'make PYTHON=missing' reports an error
* 'make PYTHON_CONFIG=missing' reports an error
Fixes: 79373082fa ("perf python: Autodetect python3 binary")
Signed-off-by: James Clark <james.clark@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20220309194313.3350126-2-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
