kernel.git/tools/perf/builtin-trace.c, branch master

perf thread: Add optional e_flags output argument to thread__e_machine

2026-01-26T21:21:20Z

The e_flags are needed to accurately compute complete perf register information for CSKY. Add the ability to read and have this value associated with a thread. This change doesn't wire up the use of the e_flags except in disasm where use already exists but just wasn't set up yet. Signed-off-by: Ian Rogers Cc: Aditya Bodkhe Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Chun-Tse Shao Cc: Guo Ren Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sergei Trofimovich Cc: Shimin Guo Cc: Stephen Brennan Cc: Swapnil Sapkal Cc: Tianyou Li Signed-off-by: Arnaldo Carvalho de Melo

perf trace: Deal with compiler const checks

2026-01-20T23:49:59Z

The strchr() function these days return const/non-const based on the arg it receives, and sometimes we need to use casts when we're dealing with variables that are used in code that needs to safely change the returned value and sometimes not (as it points to really const areas). Tweak one such case. Reviewed-by: Ian Rogers Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Switch printf("...%s", strerror(errno)) to printf("...%m")

2026-01-14T20:22:50Z

strerror() has thread safety issues, strerror_r() requires stack allocated buffers. Code in perf has already been using the "%m" formatting flag that is a widely support glibc extension to print the current errno's description. Expand the usage of this formatting flag and remove usage of strerror()/strerror_r(). Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Blake Jones Cc: Chun-Tse Shao Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Haibo Xu Cc: Howard Chu Cc: Ingo Molnar Cc: Jiri Olsa Cc: Leo Yan Cc: Peter Zijlstra Cc: Stephen Brennan Cc: Thomas Falcon Cc: Yunseong Kim Cc: Zhongqiu Han Signed-off-by: Arnaldo Carvalho de Melo

perf trace: Don't change const char strings

2025-12-17T12:30:37Z

We got away with this so far but now with fedora 44 complaining about the return value of strchr et all, lets use strdup for good measure. Reviewed-by: Ian Rogers Link: https://lore.kernel.org/r/20251211221756.96294-5-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf trace: Skip internal syscall arguments

2025-11-29T20:23:37Z

Recent changes in the linux-next kernel will add new field for syscalls to have contents in the userspace like below. # cat /sys/kernel/tracing/events/syscalls/sys_enter_write/format name: sys_enter_write ID: 758 format: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; field:int __syscall_nr; offset:8; size:4; signed:1; field:unsigned int fd; offset:16; size:8; signed:0; field:const char * buf; offset:24; size:8; signed:0; field:size_t count; offset:32; size:8; signed:0; field:__data_loc char[] __buf_val; offset:40; size:4; signed:0; print fmt: "fd: 0x%08lx, buf: 0x%08lx (%s), count: 0x%08lx", ((unsigned long)(REC->fd)), ((unsigned long)(REC->buf)), __print_dynamic_array(__buf_val, 1), ((unsigned long)(REC->count)) We have a different way to handle those arguments and this change confuses perf trace then make some tests failing. Fix it by skipping the new fields that have "__data_loc char[]" type. Maybe we can switch to this instead of the BPF augmentation later. Reviewed-by: Howard Chu Tested-by: Thomas Richter Tested-by: Steven Rostedt (Google) Cc: Steven Rostedt Cc: Howard Chu Reported-by: Thomas Richter Signed-off-by: Namhyung Kim

perf trace: Don't synthesize mmaps unless callchains are enabled

2025-10-19T02:32:30Z

Synthesizing mmaps in perf trace is unnecessary unless call chains are being generated. Signed-off-by: Ian Rogers Acked-by: Howard Chu Signed-off-by: Namhyung Kim

perf trace: Fix IS_ERR() vs NULL check bug

2025-09-19T15:42:07Z

The alloc_syscall_stats() function always returns an error pointer (ERR_PTR) on failure. So replace NULL check with IS_ERR() check after calling alloc_syscall_stats() function. Fixes: fc00897c8a3f7f57 ("perf trace: Add --summary-mode option") Reviewed-by: Ian Rogers Signed-off-by: Fushuai Wang Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo

perf trace: Add --max-summary option

2025-09-19T15:14:29Z

The --max-summary option is to limit the number of output lines for syscall summary stats. The max applies to each entries like thread and cgroups. For total summary, it will just print up to the given number. For example, $ sudo perf trace -as --max-summary 3 sleep 0.1 ThreadPoolServi (1011651), 114 events, 14.8% syscall calls errors total min avg max stddev (msec) (msec) (msec) (msec) (%) --------------- -------- ------ -------- --------- --------- --------- ------ epoll_wait 38 0 95.589 0.000 2.515 11.153 28.98% futex 9 0 0.040 0.002 0.004 0.014 28.63% read 10 0 0.037 0.003 0.004 0.005 4.67% sleep (1050529), 250 events, 32.4% syscall calls errors total min avg max stddev (msec) (msec) (msec) (msec) (%) --------------- -------- ------ -------- --------- --------- --------- ------ clock_nanosleep 1 0 100.156 100.156 100.156 100.156 0.00% execve 4 3 1.020 0.005 0.255 0.989 95.93% openat 36 17 0.416 0.003 0.012 0.029 10.58% ... And this is for per-cgroup summary using BPF. $ sudo perf trace -as --max-summary 3 --summary-mode=cgroup --bpf-summary sleep 0.1 cgroup /user.slice/user-657345.slice/user@657345.service/session.slice/org.gnome.Shell@x11.service, 12 events syscall calls errors total min avg max stddev (msec) (msec) (msec) (msec) (%) --------------- -------- ------ -------- --------- --------- --------- ------ recvmsg 8 7 0.016 0.001 0.002 0.006 39.73% ppoll 1 0 0.014 0.014 0.014 0.014 0.00% write 2 0 0.010 0.002 0.005 0.008 61.02% cgroup /user.slice/user-657345.slice/session-4.scope, 73 events syscall calls errors total min avg max stddev (msec) (msec) (msec) (msec) (%) --------------- -------- ------ -------- --------- --------- --------- ------ epoll_wait 8 0 13.461 0.010 1.683 12.235 89.66% ioctl 20 0 0.204 0.001 0.010 0.113 54.01% writev 11 0 0.164 0.004 0.015 0.042 20.34% Reviewed-by: Howard Chu Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo

perf trace: Avoid global perf_env with evsel__env

2025-07-25T17:37:58Z

There is no session in perf trace unless in replay mode, so in host mode no session can be associated with the evlist. If the evsel__env call fails resort to the host_env that's part of the trace. Remove errno_to_name as it becomes a called once 1-line function once the argument is turned into a perf_env, just call perf_env__arch_strerrno directly. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-19-irogers@google.com Signed-off-by: Namhyung Kim

perf machine: Explicitly pass in host perf_env

2025-07-25T17:37:57Z

When creating a machine for the host explicitly pass in a scoped perf_env. This removes a use of the global perf_env. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-17-irogers@google.com Signed-off-by: Namhyung Kim