From 1de3038d0082a1c2edd7a7b1b3381e38f42af0e7 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Tue, 31 Oct 2017 11:32:23 -0300 Subject: perf trace beauty kcmp: Beautify arguments For some unknown reason there is no entry in tracefs's syscalls for kcmp, i.e. no tracefs/events/syscalls/sys_{enter,exit}_kcmp, so we need to provide a data dictionary for the fields. To beautify the 'type' argument we automatically generate a strarray from tools/include/uapi/kcmp.h, the idx1 and idx2 args, nowadays used only if type == KCMP_FILE, are masked for all the other types and a lookup is made for the thread and fd to show the path, if possible, getting it from the probe:vfs_getname if in place or from procfs, races allowing. A system wide strace like tracing session, with callchains shows just one user so far in this fedora 25 machine: # perf trace --max-stack 5 -e kcmp 1502914.400 ( 0.001 ms): systemd/1 kcmp(pid1: 1 (systemd), pid2: 1 (systemd), type: FILE, idx1: 271, idx2: 25) = -1 ENOSYS Function not implemented syscall (/usr/lib64/libc-2.25.so) same_fd (/usr/lib/systemd/libsystemd-shared-233.so) service_add_fd_store (/usr/lib/systemd/systemd) service_notify_message.lto_priv.127 (/usr/lib/systemd/systemd) 1502914.407 ( 0.001 ms): systemd/1 kcmp(pid1: 1 (systemd), pid2: 1 (systemd), type: FILE, idx1: 270, idx2: 25) = -1 ENOSYS Function not implemented syscall (/usr/lib64/libc-2.25.so) same_fd (/usr/lib/systemd/libsystemd-shared-233.so) service_add_fd_store (/usr/lib/systemd/systemd) service_notify_message.lto_priv.127 (/usr/lib/systemd/systemd) The backtraces seem to agree this is really kcmp(), but this system doesn't have the sys_kcmp(), bummer: # uname -a Linux jouet 4.14.0-rc3+ #1 SMP Fri Oct 13 12:21:12 -03 2017 x86_64 x86_64 x86_64 GNU/Linux # grep kcmp /proc/kallsyms ffffffffb60b8890 W sys_kcmp $ grep CONFIG_CHECKPOINT_RESTORE ../build/v4.14.0-rc3+/.config # CONFIG_CHECKPOINT_RESTORE is not set $ So systemd uses it, good fedora kernel config has it: $ grep CONFIG_CHECKPOINT_RESTORE /boot/config-4.13.4-200.fc26.x86_64 CONFIG_CHECKPOINT_RESTORE=y [acme@jouet linux]$ /me goes to rebuild a kernel... Cc: Adrian Hunter Cc: Andrey Vagin Cc: Cyrill Gorcunov Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-gz5fca968viw8m7hryjqvrln@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-trace.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'tools/perf/builtin-trace.c') diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 0c1461416ef1..505b871fdc82 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -633,6 +633,12 @@ static struct syscall_fmt { #else [2] = { .scnprintf = SCA_HEX, /* arg */ }, }, }, #endif + { .name = "kcmp", .nr_args = 5, + .arg = { [0] = { .name = "pid1", .scnprintf = SCA_PID, }, + [1] = { .name = "pid2", .scnprintf = SCA_PID, }, + [2] = { .name = "type", .scnprintf = SCA_KCMP_TYPE, }, + [3] = { .name = "idx1", .scnprintf = SCA_KCMP_IDX, }, + [4] = { .name = "idx2", .scnprintf = SCA_KCMP_IDX, }, }, }, { .name = "keyctl", .arg = { [0] = STRARRAY(option, keyctl_options), }, }, { .name = "kill", -- cgit v1.2.3