The existing fncache can get large in testing situations. As the
bucket array is a fixed size this leads to it degrading to O(n)
performance. Use a regular hashmap that can dynamically reallocate its
array.
Before:
```
$ time perf test "Parsing of PMU event table metrics"
10.3: Parsing of PMU event table metrics : Ok
10.4: Parsing of PMU event table metrics with fake PMUs : Ok
real 0m14.132s
user 0m17.806s
sys 0m0.557s
```
After:
```
$ time perf test "Parsing of PMU event table metrics"
10.3: Parsing of PMU event table metrics : Ok
10.4: Parsing of PMU event table metrics with fake PMUs : Ok
real 0m13.287s
user 0m13.026s
sys 0m0.532s
```
Committer notes:
root@number:~# grep -m1 'model name' /proc/cpuinfo
model name : AMD Ryzen 9 9950X3D 16-Core Processor
root@number:~#
Before:
root@number:~# time perf test "Parsing of PMU event table metrics"
10.3: Parsing of PMU event table metrics : Ok
10.4: Parsing of PMU event table metrics with fake PMUs : Ok
real 0m9.277s
user 0m9.979s
sys 0m0.055s
root@number:~#
After:
root@number:~# time perf test "Parsing of PMU event table metrics"
10.3: Parsing of PMU event table metrics : Ok
10.4: Parsing of PMU event table metrics with fake PMUs : Ok
real 0m9.296s
user 0m9.361s
sys 0m0.063s
root@number:~#
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-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>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20250512194622.33258-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
On continuous testing the perf script output can be empty, or nearly
empty, causing tr/grep to exit and due to "set -e" the test traps and
fails.
Add some empty file handling that sets the test to skip and make grep
and other text rewriting failures non-fatal by adding "|| true".
Committer testing:
root@number:~# grep -m1 "model name" /proc/cpuinfo
model name : AMD Ryzen 9 9950X3D 16-Core Processor
root@number:~# perf test "Check branch stack sampling"
104: Check branch stack sampling : Ok
root@number:~#
root@number:~# perf test -vvvvvvv "Check branch stack sampling"
104: Check branch stack sampling:
--- start ---
test child forked, pid 396047
142d22-142da0 l brstack_bench
perf does have symbol 'brstack_bench'
Testing user branch stack sampling
Testing branch stack filtering permutation (any_call,CALL|IND_CALL|COND_CALL|SYSCALL|IRQ)
Testing branch stack filtering permutation (call,CALL|SYSCALL)
Testing branch stack filtering permutation (cond,COND)
Testing branch stack filtering permutation (any_ret,RET|COND_RET|SYSRET|ERET)
Testing branch stack filtering permutation (call,cond,CALL|SYSCALL|COND)
Testing branch stack filtering permutation (any_call,cond,CALL|IND_CALL|COND_CALL|IRQ|SYSCALL|COND)
Testing branch stack filtering permutation (cond,any_call,any_ret,COND|CALL|IND_CALL|COND_CALL|SYSCALL|IRQ|RET|COND_RET|SYSRET|ERET)
---- end(0) ----
104: Check branch stack sampling : Ok
root@number:~#
Signed-off-by: Ian Rogers <irogers@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: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: German Gomez <german.gomez@arm.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>
Link: https://lore.kernel.org/r/20250318161639.34446-1-irogers@google.com
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>
The Fixes commit did not add support for decoding PEBS-via-PT data_src.
Fix by adding support.
PEBS-via-PT is a feature of some E-core processors, starting with
processors based on Tremont microarchitecture. Because the kernel only
supports Intel PT features that are on all processors, there is no support
for PEBS-via-PT on hybrids.
Currently that leaves processors based on Tremont, Gracemont and Crestmont,
however there are no events on Tremont that produce data_src information,
and for Gracemont and Crestmont there are only:
mem-loads event=0xd0,umask=0x5,ldlat=3
mem-stores event=0xd0,umask=0x6
Affected processors include Alder Lake N (Gracemont), Sierra Forest
(Crestmont) and Grand Ridge (Crestmont).
Example:
# perf record -d -e intel_pt/branch=0/ -e mem-loads/aux-output/pp uname
Before:
# perf.before script --itrace=o -Fdata_src
0 |OP No|LVL N/A|SNP N/A|TLB N/A|LCK No|BLK N/A
0 |OP No|LVL N/A|SNP N/A|TLB N/A|LCK No|BLK N/A
After:
# perf script --itrace=o -Fdata_src
10268100142 |OP LOAD|LVL L1 hit|SNP None|TLB L1 or L2 hit|LCK No|BLK N/A
10450100442 |OP LOAD|LVL L2 hit|SNP None|TLB L2 miss|LCK No|BLK N/A
Fixes: 975846eddf ("perf intel-pt: Add memory information to synthesized PEBS sample")
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.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/r/20250512093932.79854-2-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>
Switch output to using a strbuf so the storage can be resized.
Add a maximum size argument to avoid too much output that may happen for
uncore events.
Rename as scnprintf is no longer used.
Committer testing:
With the patch applied:
root@number:~# perf probe -x ~/bin/perf evlist__format_evsels
Added new event:
probe_perf:evlist_format_evsels (on evlist__format_evsels in /home/acme/bin/perf)
You can now use it in all perf tools, such as:
perf record -e probe_perf:evlist_format_evsels -aR sleep 1
root@number:~# perf probe -l
probe_perf:evlist_format_evsels (on evlist__format_evsels@util/evlist.c in /home/acme/bin/perf)
root@number:~# perf trace -e probe_perf:*/max-stack=10/ perf record -e cycles,instructions,cache-misses /tmp/bla
Failed to collect 'cycles,instructions,cache-misses' for the '/tmp/bla' workload: Permission denied
0.000 perf/3893011 probe_perf:evlist_format_evsels(__probe_ip: 6183397)
evlist__format_evsels (/home/acme/bin/perf)
__cmd_record (/home/acme/bin/perf)
cmd_record (/home/acme/bin/perf)
run_builtin (/home/acme/bin/perf)
handle_internal_command (/home/acme/bin/perf)
run_argv (/home/acme/bin/perf)
main (/home/acme/bin/perf)
__libc_start_call_main (/usr/lib64/libc.so.6)
__libc_start_main@@GLIBC_2.34 (/usr/lib64/libc.so.6)
_start (/home/acme/bin/perf)
root@number:~#
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@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: Andi Kleen <ak@linux.intel.com>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Dr. David Alan Gilbert <linux@treblig.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: Levi Yun <yeoreum.yun@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>
Link: https://lore.kernel.org/r/20250402201549.4090305-4-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Prior to this patch evlist__has_hybrid would return false if the
processor wasn't hybrid or the evlist didn't contain any core
events. If the only PMU used by events was cpu_core then it would
true even though there are no cpu_atom events. For example:
```
$ perf stat --cputype=cpu_core -e '{cycles,cycles,cycles,cycles,cycles,cycles,cycles,cycles,cycles}' true
Performance counter stats for 'true':
<not counted> cpu_core/cycles/ (0.00%)
<not counted> cpu_core/cycles/ (0.00%)
<not counted> cpu_core/cycles/ (0.00%)
<not counted> cpu_core/cycles/ (0.00%)
<not counted> cpu_core/cycles/ (0.00%)
<not counted> cpu_core/cycles/ (0.00%)
<not counted> cpu_core/cycles/ (0.00%)
<not counted> cpu_core/cycles/ (0.00%)
<not counted> cpu_core/cycles/ (0.00%)
0.001981900 seconds time elapsed
0.002311000 seconds user
0.000000000 seconds sys
```
This patch changes evlist__has_hybrid to return true only if the
evlist contains events from >1 core PMU. This means the NMI watchdog
warning is shown for the case above.
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@google.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: Dr. David Alan Gilbert <linux@treblig.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: Levi Yun <yeoreum.yun@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>
Link: https://lore.kernel.org/r/20250402201549.4090305-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up fixes from the latest perf-tools pull request from Namhyung
and get perf-tools-next in line with thinngs in other areas it uses,
like tools/lib/bpf, etc.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull btrfs fixes from David Sterba:
- revert device path canonicalization, this does not work as intended
with namespaces and is not reliable in all setups
- fix crash in scrub when checksum tree is not valid, e.g. when mounted
with rescue=ignoredatacsums
- fix crash when tracepoint btrfs_prelim_ref_insert is enabled
- other minor fixups:
- open code folio_index(), meant to be used in MM code
- use matching type for sizeof in compression allocation
* tag 'for-6.15-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: open code folio_index() in btree_clear_folio_dirty_tag()
Revert "btrfs: canonicalize the device path before adding it"
btrfs: avoid NULL pointer dereference if no valid csum tree
btrfs: handle empty eb->folios in num_extent_folios()
btrfs: correct the order of prelim_ref arguments in btrfs__prelim_ref
btrfs: compression: adjust cb->compressed_folios allocation type
Pull device mapper fixes from Mikulas Patocka:
- fix reading past the end of allocated memory
- fix missing dm_put_live_table() in dm_keyslot_evict()
* tag 'for-6.15/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm: fix copying after src array boundaries
dm: add missing unlock on in dm_keyslot_evict()
Since we added --off-cpu-thresh, add tests for when a sample's off-cpu
time is above the threshold, and when it's below the threshold.
Note that the basic test performed in test_offcpu_basic() collects a
direct sample now, since sleep 1 has duration of 1000ms, higher than the
default value of --off-cpu-thresh of 500ms, resulting in a direct
sample.
An example:
$ sudo perf test offcpu
124: perf record offcpu profiling tests : Ok
$
Committer testing:
root@number:~# perf test offcpu
126: perf record offcpu profiling tests : Ok
root@number:~# perf test -v offcpu
126: perf record offcpu profiling tests : Ok
root@number:~# perf test -vv offcpu
126: perf record offcpu profiling tests:
--- start ---
test child forked, pid 1410791
Checking off-cpu privilege
Basic off-cpu test
Basic off-cpu test [Success]
Child task off-cpu test
Child task off-cpu test [Success]
Threshold test (above threshold)
Threshold test (above threshold) [Success]
Threshold test (below threshold)
Threshold test (below threshold) [Success]
---- end(0) ----
126: perf record offcpu profiling tests : Ok
root@number:~#
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: 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/20250501022809.449767-11-howardchu95@gmail.com
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>
Parse the off-cpu event using parse_event(), as bpf-output.
Call evlist__enable_evsel() on off-cpu event. This fixes the inability
to collect direct off-cpu samples on a workload, as reported by Arnaldo
Carvalho de Melo <acme@redhat.com>.
The reason being, workload sets enable_on_exec instead of calling
evlist__enable(), but off-cpu event does not attach to an executable and
execve won't be called, so the fds from perf_event_open() are not
enabled.
no-inherit should be set to 1, here's the reason:
We update the BPF perf_event map for direct off-cpu sample dumping (in
following patches), it executes as follows:
bpf_map_update_value()
bpf_fd_array_map_update_elem()
perf_event_fd_array_get_ptr()
perf_event_read_local()
In perf_event_read_local(), there is:
int perf_event_read_local(struct perf_event *event, u64 *value,
u64 *enabled, u64 *running)
{
...
/*
* It must not be an event with inherit set, we cannot read
* all child counters from atomic context.
*/
if (event->attr.inherit) {
ret = -EOPNOTSUPP;
goto out;
}
Which means no-inherit has to be true for updating the BPF perf_event
map.
Moreover, for bpf-output events, we primarily want a system-wide event
instead of a per-task event.
The reason is that in BPF's bpf_perf_event_output(), BPF uses the CPU
index to retrieve the perf_event file descriptor it outputs to.
Making a bpf-output event system-wide naturally satisfies this
requirement by mapping CPU appropriately.
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/20241108204137.2444151-4-howardchu95@gmail.com
Link: https://lore.kernel.org/r/20250501022809.449767-3-howardchu95@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull uml fix from Johannes Berg:
"There's just a single fix here for the _nofault changes that were
causing issues with clang, and then when we looked at it some other
issues seemed to exist"
* tag 'uml-for-linux-6.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
um: fix _nofault accesses
Pull SoC fixes from Arnd Bergmann:
"The main changes are once more for the NXP i.MX platform, addressing
multiple regressions in recent devicetree updates for the i.MX8MM and
i.MX6ULL SoCs, a PCIe fix for i.MX9 and a MAINTAINERS file update to
disambiguate NXP i.MX SoCs from Sony IMX image sensors.
The stm32 platform devicetree files get some compatibility fixes for
the interrupt controller node.
Another compatibility fix is done for the Arm Morello platform's cache
controller node.
The code changes are all for firmware drivers, fixing kernel-side bugs
on the Arm FF-A and SCMI drivers"
* tag 'soc-fixes-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
arm64: dts: st: Use 128kB size for aliased GIC400 register access on stm32mp23 SoCs
arm64: dts: st: Adjust interrupt-controller for stm32mp23 SoCs
arm64: dts: st: Use 128kB size for aliased GIC400 register access on stm32mp21 SoCs
arm64: dts: st: Adjust interrupt-controller for stm32mp21 SoCs
arm64: dts: st: Use 128kB size for aliased GIC400 register access on stm32mp25 SoCs
arm64: dts: st: Adjust interrupt-controller for stm32mp25 SoCs
arm64: dts: imx8mm-verdin: Link reg_usdhc2_vqmmc to usdhc2
MAINTAINERS: add exclude for dt-bindings to imx entry
ARM: dts: opos6ul: add ksz8081 phy properties
arm64: dts: imx95: Correct the range of PCIe app-reg region
arm64: dts: imx8mp: configure GPU and NPU clocks in nominal DTSI
arm64: dts: morello: Fix-up cache nodes
firmware: arm_ffa: Skip Rx buffer ownership release if not acquired
firmware: arm_scmi: Fix timeout checks on polling path
firmware: arm_scmi: Balance device refcount when destroying devices
Nathan reported [1] that when built with clang, the um kernel
crashes pretty much immediately. This turned out to be an issue
with the inline assembly I had added, when clang used %rax/%eax
for both operands. Reorder it so current->thread.segv_continue
is written first, and then the lifetime of _faulted won't have
overlap with the lifetime of segv_continue.
In the email thread Benjamin also pointed out that current->mm
is only NULL for true kernel tasks, but we could do this for a
userspace task, so the current->thread.segv_continue logic must
be lifted out of the mm==NULL check.
Finally, while looking at this, put a barrier() so the NULL
assignment to thread.segv_continue cannot be reorder before
the possibly faulting operation.
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/r/20250402221254.GA384@ax162 [1]
Fixes: d1d7f01f7c ("um: mark rodata read-only and implement _nofault accesses")
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Pull perf tools fixes from Namhyung Kim:
"Just a couple of build fixes on arm64"
* tag 'perf-tools-fixes-for-v6.15-2025-05-04' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools:
perf tools: Fix in-source libperf build
perf tools: Fix arm64 build by generating unistd_64.h
