linux-toradex.git/tools/lib/perf, branch master

perf mmap: Preserve the consumed cursor in forward mode

2026-10-27T20:01:14+00:00

perf_mmap__read_event() updates prev as it consumes forward-buffer
records. perf_mmap__read_done() then overwrites prev with a fresh
producer head, even when unread records remain.

perf_kvm__mmap_read_idx() stops after 25 records per mmap and calls
read_done(). If more records are pending, prev advances past them. The
next drain starts at that new position and skips the unread remainder.

An event arriving after the last empty read_event() and before
read_done() can also be skipped. read_done() does not itself update the
kernel's data_tail.

Only refresh prev for overwrite buffers, which need the current head as
the end of the next backward read. Leave the forward cursor at the
consumed position.

Fixes: 53172f9057e92c9b ("perf kvm: Switch to new perf_mmap__read_event() interface")
Signed-off-by: Paul Moses 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Don't restrict uncore events to PMU CPUs

2026-09-25T13:29:56+00:00

The PMU CPU map has different semantics for core and uncore PMUs.

For core PMUs, pmu_cpus contains the CPUs on which the event can be
opened. Intersect the user-requested CPU map with the PMU CPU map to
reject CPUs unsupported by the PMU.

For uncore PMUs, pmu_cpus is read from the PMU's cpumask sysfs attribute,
which lists the default CPU to open the event on per socket/die, not the
set of CPUs it can only be opened on. The user-requested CPU may override
these defaults, and the driver can redirect the event to the appropriate
control CPU.

Currently, __perf_evlist__propagate_maps() intersects the user-requested
CPU map with pmu_cpus for all PMUs. If the user-requested CPU is not in
pmu_cpus, the intersection becomes empty and the evsel is removed before
perf_event_open() is called.

Add evsel->is_pmu_uncore, set once from pmu->is_uncore at parse time,
to skip the intersection for uncore PMUs. Core PMUs, and other
non-core PMUs such as software events, breakpoints, or tracepoints,
continue to be restricted to their PMU CPU map.

Fixes: 811082e4b668db96 ("perf parse-events: Support user CPUs mixed with threads/processes")
Reviewed-by: Ian Rogers 
Assisted-by: Claude:claude-sonnet-5
Signed-off-by: Nia Su 
Signed-off-by: Arnaldo Carvalho de Melo

libperf: Document code simplification case for widening struct perf_cpu

2026-06-10T18:23:54+00:00

Add a bullet point to the libperf ABI TODO explaining the code
simplification benefit of widening struct perf_cpu.cpu from int16_t
to int: the narrow type forces defensive truncation checks at every
boundary where wider CPU indices are narrowed, and values > 32767
silently wrap to negative numbers (two's complement), bypassing
bounds validation without them.

Acked-by: Ian Rogers 
Cc: Ian Rogers 
Cc: Namhyung Kim 
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo

libperf: Document struct perf_cpu int16_t ABI limitation

2026-06-06T17:46:37+00:00

struct perf_cpu.cpu is int16_t, limiting perf to 32767 CPUs.  This is
part of the libperf ABI (returned by value from perf_cpu_map__cpu() and
friends), so widening it requires an ABI bump.

Add a comment on the struct definition noting this, and create a TODO
file to collect future ABI changes so they can be batched into a single
version bump.

Cc: Ian Rogers 
Cc: Namhyung Kim 
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix event_contains() macro to verify full field extent

2026-05-29T14:44:19+00:00

event_contains() checked whether a field's start offset was within
the event (header.size > offsetof), but not whether the full field
fit.  A crafted event with header.size = offsetof(field) + 1 would
pass the check, but an 8-byte access (bswap_64, direct read) would
overrun the event boundary by up to 7 bytes.

Fix the macro to verify the complete field:

  header.size >= offsetof(field) + sizeof(field)

Also update all callers that check event_contains(time_cycles) but
access later fields (time_mask, cap_user_time_zero,
cap_user_time_short) to check for cap_user_time_short — the last
field accessed — so the entire extended block is verified:
tsc.c, arm-spe.c, cs-etm.c, jitdump.c.

Note: session.c's perf_event__time_conv_swap() also guards on
time_cycles but accesses time_mask — a pre-existing issue not
introduced by this macro change.  It is fixed by a later patch
in this series ("perf session: Add validated swap
infrastructure with null-termination checks"), which decouples
time_cycles and time_mask into independent per-field
event_contains() checks.  The struct assignment overread
(session->time_conv = event->time_conv copies sizeof on a
potentially shorter event) is separately fixed by "perf
session: Use bounded copy for PERF_RECORD_TIME_CONV".

Reported-by: sashiko-bot@kernel.org # Running on a local machine
Reviewed-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Assisted-by: Claude:claude-opus-4.6-1m
Signed-off-by: Arnaldo Carvalho de Melo

libperf cpumap: Make index and nr types unsigned

2026-04-01T21:50:53+00:00

The index into the cpumap array and the number of entries within the
array can never be negative, so let's make them unsigned. This is
prompted by reports that gcc 13 with -O6 is giving a
alloc-size-larger-than errors. The change makes the cpumap changes and
then updates the declaration of index variables throughout perf and
libperf to be unsigned. The two things are hard to separate as
compiler warnings about mixing signed and unsigned types breaks the
build.

Reported-by: Chingbin Li 
Closes: https://lore.kernel.org/lkml/20260212025127.841090-1-liqb365@163.com/
Tested-by: Chingbin Li 
Signed-off-by: Ian Rogers 
Signed-off-by: Namhyung Kim

perf evlist: Special map propagation for tool events that read on 1 CPU

2026-02-10T12:33:28+00:00

Tool events like duration_time don't need a perf_cpu_map that contains
all online CPUs.

Having such a perf_cpu_map causes overheads when iterating between
events for CPU affinity.

During parsing mark events that just read on a single CPU map index as
such, then during map propagation set up the evsel's CPUs and thereby
the evlists accordingly.

The setting cannot be done early in parsing as user CPUs are only fully
known when evlist__create_maps is called.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Andres Freund 
Cc: Dapeng Mi 
Cc: Dr. David Alan Gilbert 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Thomas Falcon 
Cc: Thomas Richter 
Cc: Yang Li 
Signed-off-by: Arnaldo Carvalho de Melo

libperf build: Always place libperf includes first

2026-02-03T21:01:27+00:00

When building tools/perf the CFLAGS can contain a directory for the
installed headers.

As the headers may be being installed while building libperf.a this can
cause headers to be partially installed and found in the include path
while building an object file for libperf.a.

The installed header may reference other installed headers that are
missing given the partial nature of the install and then the build fails
with a missing header file.

Avoid this by ensuring the libperf source headers are always first in
the CFLAGS.

Fixes: 3143504918105156 ("libperf: Make libperf.a part of the perf build")
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Signed-off-by: Arnaldo Carvalho de Melo

Revert "perf tools: Fix arm64 build by generating unistd_64.h"

2026-01-26T20:08:43+00:00

This reverts:

commit 8988c4b91945173a ("perf tools: Fix in-source libperf build")
commit bfb713ea53c746b0 ("perf tools: Fix arm64 build by generating unistd_64.h")

Since we now have a static unistd_64.h for the arm64 build, there is no
need to generate unistd_64.h in libperf.  Revert all patches related to
generating unistd_64.h.

Reviewed-by: James Clark 
Signed-off-by: Leo Yan 
Cc: Adrian Hunter 
Cc: Arnd Bergmann 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Signed-off-by: Arnaldo Carvalho de Melo

perf sched stats: Add schedstat v17 support

2026-01-22T15:31:51+00:00

The /proc/schedstat file output is standardized with version number.

Add support to record and raw dump v17 version layout.

Version 17 of schedstats removed 'lb_imbalance' field as it has no
significance anymore and instead added more relevant fields namely
'lb_imbalance_load', 'lb_imbalance_util', 'lb_imbalance_task' and
'lb_imbalance_misfit'.

The domain field prints the name of the corresponding sched domain from
this version onwards.

Co-developed-by: Ravi Bangoria 
Signed-off-by: Ravi Bangoria 
Signed-off-by: Swapnil Sapkal 
Tested-by: Chen Yu 
Acked-by: Ian Rogers 
Acked-by: Peter Zijlstra 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Anubhav Shelat 
Cc: Ben Gainey 
Cc: Blake Jones 
Cc: Chun-Tse Shao 
Cc: David Vernet 
Cc: Dmitriy Vyukov 
Cc: Dr. David Alan Gilbert 
Cc: Gautham Shenoy 
Cc: Graham Woodward 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Juri Lelli 
Cc: K Prateek Nayak 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Madadi Vineeth Reddy 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Sandipan Das 
Cc: Santosh Shukla 
Cc: Shrikanth Hegde 
Cc: Steven Rostedt (VMware) 
Cc: Tejun Heo 
Cc: Thomas Falcon 
Cc: Tim Chen 
Cc: Vincent Guittot 
Cc: Yang Jihong 
Cc: Yujie Liu 
Cc: Zhongqiu Han 
Signed-off-by: Arnaldo Carvalho de Melo