The '-o' option exists for the SVG creation but not for `perf
timechart record`. Add to better allow testing.
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Save samples with deferred callchains in a separate list and deliver
them after merging the user callchains. If users don't want to merge
they can set tool->merge_deferred_callchains to false to prevent the
behavior.
With previous result, now perf script will show the merged callchains.
$ perf script
...
pwd 2312 121.163435: 249113 cpu/cycles/P:
ffffffff845b78d8 __build_id_parse.isra.0+0x218 ([kernel.kallsyms])
ffffffff83bb5bf6 perf_event_mmap+0x2e6 ([kernel.kallsyms])
ffffffff83c31959 mprotect_fixup+0x1e9 ([kernel.kallsyms])
ffffffff83c31dc5 do_mprotect_pkey+0x2b5 ([kernel.kallsyms])
ffffffff83c3206f __x64_sys_mprotect+0x1f ([kernel.kallsyms])
ffffffff845e6692 do_syscall_64+0x62 ([kernel.kallsyms])
ffffffff8360012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms])
7f18fe337fa7 mprotect+0x7 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
7f18fe330e0f _dl_sysdep_start+0x7f (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
7f18fe331448 _dl_start_user+0x0 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
...
The old output can be get using --no-merge-callchain option.
Also perf report can get the user callchain entry at the end.
$ perf report --no-children --stdio -q -S __build_id_parse.isra.0
# symbol: __build_id_parse.isra.0
8.40% pwd [kernel.kallsyms]
|
---__build_id_parse.isra.0
perf_event_mmap
mprotect_fixup
do_mprotect_pkey
__x64_sys_mprotect
do_syscall_64
entry_SYSCALL_64_after_hwframe
mprotect
_dl_sysdep_start
_dl_start_user
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Add a new callchain record mode option for deferred callchains. For now
it only works with FP (frame-pointer) mode.
And add the missing feature detection logic to clear the flag on old
kernels.
$ perf record --call-graph fp,defer -vv true
...
------------------------------------------------------------
perf_event_attr:
type 0 (PERF_TYPE_HARDWARE)
size 136
config 0 (PERF_COUNT_HW_CPU_CYCLES)
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|CALLCHAIN|PERIOD
read_format ID|LOST
disabled 1
inherit 1
mmap 1
comm 1
freq 1
enable_on_exec 1
task 1
sample_id_all 1
mmap2 1
comm_exec 1
ksymbol 1
bpf_event 1
defer_callchain 1
defer_output 1
------------------------------------------------------------
sys_perf_event_open: pid 162755 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open failed, error -22
switching off deferred callchain support
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
FEAT_SPE_EFT and FEAT_SPE_FDS etc have new user facing format attributes
so document them. Also document existing 'event_filter' bits that were
missing from the doc and the fact that latency values are stored in the
weight field.
Reviewed-by: Leo Yan <leo.yan@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The NO_AUXTRACE build option was used when the __get_cpuid feature
test failed or if it was provided on the command line. The option no
longer avoids a dependency on a library and so having the option is
just adding complexity to the code base. Remove the option
CONFIG_AUXTRACE from Build files and HAVE_AUXTRACE_SUPPORT by assuming
it is always defined.
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Perf c2c report currently specified the code address and source:line
information in the cacheline browser, while it is lack of annotation
support like perf report to directly show the disassembly code for
the particular symbol shared that same cacheline. This patches add
a key 'a' binding to the cacheline browser which reuse the annotation
browser to show the disassembly view for easier analysis of cacheline
contentions.
Signed-off-by: Tianyou Li <tianyou.li@intel.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Reviewed-by: Jiebin Sun <jiebin.sun@intel.com>
Reviewed-by: Pan Deng <pan.deng@intel.com>
Reviewed-by: Zhiguo Zhou <zhiguo.zhou@intel.com>
Reviewed-by: Wangyang Guo <wangyang.guo@intel.com>
Tested-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
There can be a significant gap in memset/memcpy performance depending
on the size of the region being operated on.
With chunk-size=4kb:
$ echo madvise > /sys/kernel/mm/transparent_hugepage/enabled
$ perf bench mem memset -p 4kb -k 4kb -s 4gb -l 10 -f x86-64-stosq
# Running 'mem/memset' benchmark:
# function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S)
# Copying 4gb bytes ...
13.011655 GB/sec
With chunk-size=1gb:
$ echo madvise > /sys/kernel/mm/transparent_hugepage/enabled
$ perf bench mem memset -p 4kb -k 1gb -s 4gb -l 10 -f x86-64-stosq
# Running 'mem/memset' benchmark:
# function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S)
# Copying 4gb bytes ...
21.936355 GB/sec
So, allow the user to specify the chunk-size.
The default value is identical to the total size of the region, which
preserves current behaviour.
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Raghavendra K T <raghavendra.kt@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Page sizes that can be selected: 4KB, 2MB, 1GB.
Both the reservation and node from which hugepages are allocated
from are expected to be addressed by the user.
An example of page-size selection:
$ perf bench mem memset -s 4gb -p 2mb
# Running 'mem/memset' benchmark:
# function 'default' (Default memset() provided by glibc)
# Copying 4gb bytes ...
14.919194 GB/sec
# function 'x86-64-unrolled' (unrolled memset() in arch/x86/lib/memset_64.S)
# Copying 4gb bytes ...
11.514503 GB/sec
# function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S)
# Copying 4gb bytes ...
12.600568 GB/sec
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Raghavendra K T <raghavendra.kt@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The function parse_events__sort_events_and_fix_groups is needed to fix
uncore events like:
```
$ perf stat -e '{data_read,data_write}' ...
```
so that the multiple uncore PMUs have a group each of data_read and
data_write events.
The same function will perform architecture sorting and group fixing,
in particular for Intel topdown/perf-metric events. Grouping multiple
perf metric events together causes perf_event_open to fail as the
group can only support one. This means command lines like:
```
$ perf stat -e 'slots,slots' ...
```
fail as the slots events are forced into a group together to try to
satisfy the perf-metric event constraints.
As the user may know better than
parse_events__sort_events_and_fix_groups add a 'X' modifier to skip
its regrouping behavior. This allows the following to succeed rather
than fail on the second slots event being opened:
```
$ perf stat -e 'slots,slots:X' -a sleep 1
Performance counter stats for 'system wide':
6,834,154,071 cpu_core/slots/ (50.13%)
5,548,629,453 cpu_core/slots/X (49.87%)
1.002634606 seconds time elapsed
```
Closes: https://lore.kernel.org/lkml/20250822082233.1850417-1-dapeng1.mi@linux.intel.com/
Reported-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Reported-by: Xudong Hao <xudong.hao@intel.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Yoshihiro Furudera <fj5100bi@fujitsu.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
On hybrid systems, events like msr/tsc/ will aggregate counts across
all CPUs. Often metrics only want a value like msr/tsc/ for the cores
on which the metric is being computed. Listing each CPU with terms
cpu=0,cpu=1.. is laborious and would need to be encoded for all
variations of a CPU model.
Allow the cpumask from a PMU to be an argument to the cpu term. For
example in the following the cpumask of the cstate_pkg PMU selects the
CPUs to count msr/tsc/ counter upon:
```
$ cat /sys/bus/event_source/devices/cstate_pkg/cpumask
0
$ perf stat -A -e 'msr/tsc,cpu=cstate_pkg/' -a sleep 0.1
Performance counter stats for 'system wide':
CPU0 252,621,253 msr/tsc,cpu=cstate_pkg/
0.101184092 seconds time elapsed
```
As the cpu term is now also allowed to be a string, allow it to encode
a range of CPUs (a list can't be supported as ',' is already a special
token).
The "event qualifiers" section of the `perf list` man page is updated
to detail the additional behavior. The man page formatting is tidied
up in this section, as it was incorrectly appearing within the
"parameterized events" section.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250719030517.1990983-5-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In addition to the function latency, it can measure events latencies.
Some kernel tracepoints are paired and it's menningful to measure how
long it takes between the two events. The latency is tracked for the
same thread.
Currently it only uses BPF to do the work but it can be lifted later.
Instead of having separate a BPF program for each tracepoint, it only
uses generic 'event_begin' and 'event_end' programs to attach to any
(raw) tracepoints.
$ sudo perf ftrace latency -a -b --hide-empty \
-e i915_request_wait_begin,i915_request_wait_end -- sleep 1
# DURATION | COUNT | GRAPH |
256 - 512 us | 4 | ###### |
2 - 4 ms | 2 | ### |
4 - 8 ms | 12 | ################### |
8 - 16 ms | 10 | ################ |
# statistics (in usec)
total time: 194915
avg time: 6961
max time: 12855
min time: 373
count: 28
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250714052143.342851-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This creates a config option that detects libbpf's ability to display
character arrays as strings, which was just added to the BPF tree
(https://git.kernel.org/bpf/bpf-next/c/87c9c79a02b4).
To test this change, I built perf (from later in this patch set) with:
- static libbpf (default, using source from kernel tree)
- dynamic libbpf (LIBBPF_DYNAMIC=1 LIBBPF_INCLUDE=/usr/local/include)
For both the static and dynamic versions, I used headers with and without
the ".emit_strings" option.
I verified that of the four resulting binaries, the two with
".emit_strings" would successfully record BPF_METADATA events, and the two
without wouldn't. All four binaries would successfully display
BPF_METADATA events, because the relevant bit of libbpf code is only used
during "perf record".
Signed-off-by: Blake Jones <blakejones@google.com>
Link: https://lore.kernel.org/r/20250612194939.162730-2-blakejones@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The original PERF_RECORD_COMPRESS is not 8-byte aligned, which can cause
asan runtime error:
# Build with asan
$ make -C tools/perf O=/tmp/perf DEBUG=1 EXTRA_CFLAGS="-O0 -g -fno-omit-frame-pointer -fsanitize=undefined"
# Test success with many asan runtime errors:
$ /tmp/perf/perf test "Zstd perf.data compression/decompression" -vv
83: Zstd perf.data compression/decompression:
...
util/session.c:1959:13: runtime error: member access within misaligned address 0x7f69e3f99653 for type 'union perf_event', which requires 13 byte alignment
0x7f69e3f99653: note: pointer points here
d0 3a 50 69 44 00 00 00 00 00 08 00 bb 07 00 00 00 00 00 00 44 00 00 00 00 00 00 00 ff 07 00 00
^
util/session.c:2163:22: runtime error: member access within misaligned address 0x7f69e3f99653 for type 'union perf_event', which requires 8 byte alignment
0x7f69e3f99653: note: pointer points here
d0 3a 50 69 44 00 00 00 00 00 08 00 bb 07 00 00 00 00 00 00 44 00 00 00 00 00 00 00 ff 07 00 00
^
...
Since there is no way to align compressed data in zstd compression, this
patch add a new event type `PERF_RECORD_COMPRESSED2`, which adds a field
`data_size` to specify the actual compressed data size.
The `header.size` contains the total record size, including the padding
at the end to make it 8-byte aligned.
Tested with `Zstd perf.data compression/decompression`
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ben Gainey <ben.gainey@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303183646.327510-1-ctshao@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Sometimes we need to analyze the data in process level but current sort
keys only work on thread level. Let's add 'tgid' sort key for that as
'pid' is already taken for thread.
This will look mostly the same, but it only uses tgid instead of tid.
Here's an example of a process with two threads (thloop).
$ perf record -- perf test -w thloop
$ perf report --stdio -s tgid,pid -H
...
#
# Overhead Tgid:Command / Pid:Command
# ........... ..........................
#
100.00% 2018407:perf
50.34% 2018407:perf
49.66% 2018409:perf
Suggested-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250509210421.197245-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The -C option allows the CPUs for a list of events to be specified but
its not possible to set the CPU for a single event. Add a term to
allow this. The term isn't a general CPU list due to ',' already being
a special character in event parsing instead multiple cpu= terms may
be provided and they will be merged/unioned together.
An example of mixing different types of events counted on different CPUs:
```
$ perf stat -A -C 0,4-5,8 -e "instructions/cpu=0/,l1d-misses/cpu=4,cpu=5/,inst_retired.any/cpu=8/,cycles" -a sleep 0.1
Performance counter stats for 'system wide':
CPU0 6,979,225 instructions/cpu=0/ # 0.89 insn per cycle
CPU4 75,138 cpu/l1d-misses/
CPU5 1,418,939 cpu/l1d-misses/
CPU8 797,553 cpu/inst_retired.any,cpu=8/
CPU0 7,845,302 cycles
CPU4 6,546,859 cycles
CPU5 185,915,438 cycles
CPU8 2,065,668 cycles
0.112449242 seconds time elapsed
```
Committer testing:
root@number:~# grep -m1 "model name" /proc/cpuinfo
model name : AMD Ryzen 9 9950X3D 16-Core Processor
root@number:~# perf stat -A -e "instructions/cpu=0/,instructions,l1d-misses/cpu=4,cpu=5/,cycles" -a sleep 0.1
Performance counter stats for 'system wide':
CPU0 2,398,351 instructions/cpu=0/ # 0.44 insn per cycle
CPU0 2,398,152 instructions # 0.44 insn per cycle
CPU1 1,265,634 instructions # 0.49 insn per cycle
CPU2 606,087 instructions # 0.50 insn per cycle
CPU3 4,025,752 instructions # 0.52 insn per cycle
CPU4 4,236,810 instructions # 0.53 insn per cycle
CPU5 3,984,832 instructions # 0.66 insn per cycle
CPU6 434,132 instructions # 0.44 insn per cycle
CPU7 65,752 instructions # 0.41 insn per cycle
CPU8 459,083 instructions # 0.48 insn per cycle
CPU9 6,464,161 instructions # 1.31 insn per cycle
<SNIP>
root@number:~# perf stat -e "instructions/cpu=0/,instructions,l1d-misses/cpu=4,cpu=5/,cycles" -a sleep 0.
Performance counter stats for 'system wide':
144,822 instructions/cpu=0/ # 0.03 insn per cycle
4,666,114 instructions # 0.93 insn per cycle
2,583 l1d-misses
4,993,633 cycles
0.000868512 seconds time elapsed
root@number:~#
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20250403194337.40202-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
On systems with many CPUs, recording extra context switch events can be
excessive and unnecessary. Add perf config intel-pt.all-switch-events=false
to control the behaviour.
Example:
# perf config intel-pt.all-switch-events=false
# perf record -eintel_pt//u uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.082 MB perf.data ]
# perf script -D | grep PERF_RECORD_SWITCH | awk '{print $5}' | uniq -c
5 PERF_RECORD_SWITCH
# perf config intel-pt.all-switch-events=true
# perf record -eintel_pt//u uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.102 MB perf.data ]
# perf script -D | grep PERF_RECORD_SWITCH | awk '{print $5}' | uniq -c
180 PERF_RECORD_SWITCH_CPU_WIDE
Committer testing:
While doing a make -j28 allmodconfig:
root@five:~# grep "model name" -m1 /proc/cpuinfo
model name : Intel(R) Core(TM) i7-14700K
root@five:~#
root@five:~# perf config intel-pt.all-switch-events=false
root@five:~# perf record -e intel_pt//u uname
Linux
[ perf record: Woken up 2 times to write data ]
[ perf record: Captured and wrote 0.019 MB perf.data ]
root@five:~# perf report --stats | grep SWITCH_CPU_WIDE
root@five:~#
root@five:~# perf config intel-pt.all-switch-events=true
root@five:~# perf record -e intel_pt//u uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.047 MB perf.data ]
root@five:~# perf report --stats | grep SWITCH_CPU_WIDE
SWITCH_CPU_WIDE events: 542 (96.4%)
root@five:~#
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20250512093932.79854-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This is to slow down lock acquistion (on contention locks) deliberately.
A possible use case is to estimate impact on application performance by
optimization of kernel locking behavior. By delaying the lock it can
simulate the worse condition as a control group, and then compare with
the current behavior as a optimized condition.
The syntax is 'time@function' and the time can have unit suffix like
"us" and "ms". For example, I ran a simple test like below.
$ sudo perf lock con -abl -L tasklist_lock -- \
sh -c 'for i in $(seq 1000); do sleep 1 & done; wait'
contended total wait max wait avg wait address symbol
92 1.18 ms 199.54 us 12.79 us ffffffff8a806080 tasklist_lock (rwlock)
The contention count was 92 and the average wait time was around 10 us.
But if I add 100 usec of delay to the tasklist_lock,
$ sudo perf lock con -abl -L tasklist_lock -J 100us@tasklist_lock -- \
sh -c 'for i in $(seq 1000); do sleep 1 & done; wait'
contended total wait max wait avg wait address symbol
190 15.67 ms 230.10 us 82.46 us ffffffff8a806080 tasklist_lock (rwlock)
The contention count increased and the average wait time was up closed
to 100 usec. If I increase the delay even more,
$ sudo perf lock con -abl -L tasklist_lock -J 1ms@tasklist_lock -- \
sh -c 'for i in $(seq 1000); do sleep 1 & done; wait'
contended total wait max wait avg wait address symbol
1002 2.80 s 3.01 ms 2.80 ms ffffffff8a806080 tasklist_lock (rwlock)
Now every sleep process had contention and the wait time was more than 1
msec. This is on my 4 CPU laptop so I guess one CPU has the lock while
other 3 are waiting for it mostly.
For simplicity, it only supports global locks for now.
Committer testing:
root@number:~# grep -m1 'model name' /proc/cpuinfo
model name : AMD Ryzen 9 9950X3D 16-Core Processor
root@number:~# perf lock con -abl -L tasklist_lock -- sh -c 'for i in $(seq 1000); do sleep 1 & done; wait'
contended total wait max wait avg wait address symbol
142 453.85 us 25.39 us 3.20 us ffffffffae808080 tasklist_lock (rwlock)
root@number:~# perf lock con -abl -L tasklist_lock -J 100us@tasklist_lock -- sh -c 'for i in $(seq 1000); do sleep 1 & done; wait'
contended total wait max wait avg wait address symbol
1040 2.39 s 3.11 ms 2.30 ms ffffffffae808080 tasklist_lock (rwlock)
root@number:~# perf lock con -abl -L tasklist_lock -J 1ms@tasklist_lock -- sh -c 'for i in $(seq 1000); do sleep 1 & done; wait'
contended total wait max wait avg wait address symbol
1025 24.72 s 31.01 ms 24.12 ms ffffffffae808080 tasklist_lock (rwlock)
root@number:~#
Suggested-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20250509171950.183591-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Specify the threshold for dumping offcpu samples with --off-cpu-thresh,
the unit is milliseconds. Default value is 500ms.
Example:
perf record --off-cpu --off-cpu-thresh 824
The example above collects direct off-cpu samples where the off-cpu time
is longer than 824ms.
Committer testing:
After commenting out the end off-cpu dump to have just the ones that are
added right after the task is scheduled back, and using a threshould of
1000ms, we see some periods (the 5th column, just before "offcpu-time"
in the 'perf script' output) that are over 1000.000.000 nanoseconds:
root@number:~# perf record --off-cpu --off-cpu-thresh 10000
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 3.902 MB perf.data (34335 samples) ]
root@number:~# perf script
<SNIP>
Isolated Web Co 59932 [028] 63839.594437: 1000049427 offcpu-time:
7fe63c7976c2 __syscall_cancel_arch_end+0x0 (/usr/lib64/libc.so.6)
7fe63c78c04c __futex_abstimed_wait_common+0x7c (/usr/lib64/libc.so.6)
7fe63c78e928 pthread_cond_timedwait@@GLIBC_2.3.2+0x178 (/usr/lib64/libc.so.6)
5599974a9fe7 mozilla::detail::ConditionVariableImpl::wait_for(mozilla::detail::MutexImpl&, mozilla::BaseTimeDuration<mozilla::TimeDurationValueCalculator> const&)+0xe7 (/usr/lib64/fir>
100000000 [unknown] ([unknown])
swapper 0 [025] 63839.594459: 195724 cycles:P: ffffffffac328270 read_tsc+0x0 ([kernel.kallsyms])
Isolated Web Co 59932 [010] 63839.594466: 1000055278 offcpu-time:
7fe63c7976c2 __syscall_cancel_arch_end+0x0 (/usr/lib64/libc.so.6)
7fe63c78ba24 __syscall_cancel+0x14 (/usr/lib64/libc.so.6)
7fe63c804c4e __poll+0x1e (/usr/lib64/libc.so.6)
7fe633b0d1b8 PollWrapper(_GPollFD*, unsigned int, int) [clone .lto_priv.0]+0xf8 (/usr/lib64/firefox/libxul.so)
10000002c [unknown] ([unknown])
swapper 0 [027] 63839.594475: 134433 cycles:P: ffffffffad4c45d9 irqentry_enter+0x19 ([kernel.kallsyms])
swapper 0 [028] 63839.594499: 215838 cycles:P: ffffffffac39199a switch_mm_irqs_off+0x10a ([kernel.kallsyms])
MediaPD~oder #1 1407676 [027] 63839.594514: 134433 cycles:P: 7f982ef5e69f dct_IV(int*, int, int*)+0x24f (/usr/lib64/libfdk-aac.so.2.0.0)
swapper 0 [024] 63839.594524: 267411 cycles:P: ffffffffad4c6ee6 poll_idle+0x56 ([kernel.kallsyms])
MediaSu~sor #75 1093827 [026] 63839.594555: 332652 cycles:P: 55be753ad030 moz_xmalloc+0x200 (/usr/lib64/firefox/firefox)
swapper 0 [027] 63839.594616: 160548 cycles:P: ffffffffad144840 menu_select+0x570 ([kernel.kallsyms])
Isolated Web Co 14019 [027] 63839.595120: 1000050178 offcpu-time:
7fc9537cc6c2 __syscall_cancel_arch_end+0x0 (/usr/lib64/libc.so.6)
7fc9537c104c __futex_abstimed_wait_common+0x7c (/usr/lib64/libc.so.6)
7fc9537c3928 pthread_cond_timedwait@@GLIBC_2.3.2+0x178 (/usr/lib64/libc.so.6)
7fc95372a3c8 pt_TimedWait+0xb8 (/usr/lib64/libnspr4.so)
7fc95372a8d8 PR_WaitCondVar+0x68 (/usr/lib64/libnspr4.so)
7fc94afb1f7c WatchdogMain(void*)+0xac (/usr/lib64/firefox/libxul.so)
7fc947498660 [unknown] ([unknown])
7fc9535fce88 [unknown] ([unknown])
7fc94b620e60 WatchdogManager::~WatchdogManager()+0x0 (/usr/lib64/firefox/libxul.so)
fff8548387f8b48 [unknown] ([unknown])
swapper 0 [003] 63839.595712: 212948 cycles:P: ffffffffacd5b865 acpi_os_read_port+0x55 ([kernel.kallsyms])
<SNIP>
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Suggested-by: Ian Rogers <irogers@google.com>
Suggested-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Howard Chu <howardchu95@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Gautam Menghani <gautam@linux.ibm.com>
Tested-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241108204137.2444151-2-howardchu95@gmail.com
Link: https://lore.kernel.org/r/20250501022809.449767-10-howardchu95@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When -s/--summary option is used, it doesn't need (augmented) arguments
of syscalls. Let's skip the augmentation and load another small BPF
program to collect the statistics in the kernel instead of copying the
data to the ring-buffer to calculate the stats in userspace. This will
be much more light-weight than the existing approach and remove any lost
events.
Let's add a new option --bpf-summary to control this behavior. I cannot
make it default because there's no way to get e_machine in the BPF which
is needed for detecting different ABIs like 32-bit compat mode.
No functional changes intended except for no more LOST events. :)
$ sudo ./perf trace -as --summary-mode=total --bpf-summary sleep 1
Summary of events:
total, 6194 events
syscall calls errors total min avg max stddev
(msec) (msec) (msec) (msec) (%)
--------------- -------- ------ -------- --------- --------- --------- ------
epoll_wait 561 0 4530.843 0.000 8.076 520.941 18.75%
futex 693 45 4317.231 0.000 6.230 500.077 21.98%
poll 300 0 1040.109 0.000 3.467 120.928 17.02%
clock_nanosleep 1 0 1000.172 1000.172 1000.172 1000.172 0.00%
ppoll 360 0 872.386 0.001 2.423 253.275 41.91%
epoll_pwait 14 0 384.349 0.001 27.453 380.002 98.79%
pselect6 14 0 108.130 7.198 7.724 8.206 0.85%
nanosleep 39 0 43.378 0.069 1.112 10.084 44.23%
...
Reviewed-by: Howard Chu <howardchu95@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20250326044001.3503432-1-namhyung@kernel.org
[ Added fixup sent from Namhyung in response to my report to make it also dependent on CONFIG_TRACE ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The following commits added new fields/flags to the branch stack field
list:
commit 1f48989cdc ("perf script: Output branch sample type")
commit 6ade6c6460 ("perf script: Show branch speculation info")
commit 1e66dcff7b ("perf script: Add not taken event for branch stack")
Update brstack syntax documentation to be consistent with the latest
branch stack field list. Improve the descriptions to help users
interpret the fields accurately.
Signed-off-by: Yujie Liu <yujie.liu@intel.com>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Sandipan Das <sandipan.das@amd.com>
Link: https://lore.kernel.org/r/20250312072329.419020-1-yujie.liu@intel.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This patch parses `owner_lock_stat` into a RB tree, enabling ordered
reporting of owner lock statistics with stack traces. It also updates
the documentation for the `-o` option in contention mode, decouples `-o`
from `-t`, and issues a warning to inform users about the new behavior
of `-ov`.
Example output:
$ sudo ~/linux/tools/perf/perf lock con -abvo -Y mutex-spin -E3 perf bench sched pipe
...
contended total wait max wait avg wait type caller
171 1.55 ms 20.26 us 9.06 us mutex pipe_read+0x57
0xffffffffac6318e7 pipe_read+0x57
0xffffffffac623862 vfs_read+0x332
0xffffffffac62434b ksys_read+0xbb
0xfffffffface604b2 do_syscall_64+0x82
0xffffffffad00012f entry_SYSCALL_64_after_hwframe+0x76
36 193.71 us 15.27 us 5.38 us mutex pipe_write+0x50
0xffffffffac631ee0 pipe_write+0x50
0xffffffffac6241db vfs_write+0x3bb
0xffffffffac6244ab ksys_write+0xbb
0xfffffffface604b2 do_syscall_64+0x82
0xffffffffad00012f entry_SYSCALL_64_after_hwframe+0x76
4 51.22 us 16.47 us 12.80 us mutex do_epoll_wait+0x24d
0xffffffffac691f0d do_epoll_wait+0x24d
0xffffffffac69249b do_epoll_pwait.part.0+0xb
0xffffffffac693ba5 __x64_sys_epoll_pwait+0x95
0xfffffffface604b2 do_syscall_64+0x82
0xffffffffad00012f entry_SYSCALL_64_after_hwframe+0x76
=== owner stack trace ===
3 31.24 us 15.27 us 10.41 us mutex pipe_read+0x348
0xffffffffac631bd8 pipe_read+0x348
0xffffffffac623862 vfs_read+0x332
0xffffffffac62434b ksys_read+0xbb
0xfffffffface604b2 do_syscall_64+0x82
0xffffffffad00012f entry_SYSCALL_64_after_hwframe+0x76
...
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Tested-by: Athira Rajeev <atrajeev@linux.ibm.com>
Link: https://lore.kernel.org/r/20250227003359.732948-5-ctshao@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In sysfs, the perf events are all located in
/sys/bus/event_source/devices/ but some places ended up hard-coding the
location to be at the root of /sys/devices/ which could be very risky as
you do not exactly know what type of device you are accessing in sysfs
at that location.
So fix this all up by properly pointing everything at the bus device
list instead of the root of the sysfs devices/ tree.
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/2025021955-implant-excavator-179d@gregkh
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The --summary-mode option will select how to show the syscall summary at
the end. By default, it'll show the summary for each thread and it's
the same as if --summary-mode=thread is passed.
The other option is to show total summary, which is --summary-mode=total.
I'd like to have this instead of a separate option like --total-summary
because we may want to add a new summary mode (by cgroup) later.
$ sudo ./perf trace -as --summary-mode=total sleep 1
Summary of events:
total, 21580 events
syscall calls errors total min avg max stddev
(msec) (msec) (msec) (msec) (%)
--------------- -------- ------ -------- --------- --------- --------- ------
epoll_wait 1305 0 14716.712 0.000 11.277 551.529 8.87%
futex 1256 89 13331.197 0.000 10.614 733.722 15.49%
poll 669 0 6806.618 0.000 10.174 459.316 11.77%
ppoll 220 0 3968.797 0.000 18.040 516.775 25.35%
clock_nanosleep 1 0 1000.027 1000.027 1000.027 1000.027 0.00%
epoll_pwait 21 0 592.783 0.000 28.228 522.293 88.29%
nanosleep 16 0 60.515 0.000 3.782 10.123 33.33%
ioctl 510 0 4.284 0.001 0.008 0.182 8.84%
recvmsg 1434 775 3.497 0.001 0.002 0.174 6.37%
write 1393 0 2.854 0.001 0.002 0.017 1.79%
read 1063 100 2.236 0.000 0.002 0.083 5.11%
...
Reviewed-by: Howard Chu <howardchu95@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20250205205443.1986408-5-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
