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Its used from trace__run(), for the 'perf trace' live mode, i.e. its
strace-like, non-perf.data file processing mode, the most common one.
The trace__run() function will set trace->host using machine__new_host()
that is supposed to give a machine instance representing the running
machine, and since we'll use perf_env__arch_strerrno() to get the right
errno -> string table, we need to use machine->env, so initialize it in
machine__new_host().
Before the patch:
(gdb) run trace --errno-summary -a sleep 1
<SNIP>
Summary of events:
gvfs-afc-volume (3187), 2 events, 0.0%
syscall calls errors total min avg max stddev
(msec) (msec) (msec) (msec) (%)
--------------- -------- ------ -------- --------- --------- --------- ------
pselect6 1 0 0.000 0.000 0.000 0.000 0.00%
GUsbEventThread (3519), 2 events, 0.0%
syscall calls errors total min avg max stddev
(msec) (msec) (msec) (msec) (%)
--------------- -------- ------ -------- --------- --------- --------- ------
poll 1 0 0.000 0.000 0.000 0.000 0.00%
<SNIP>
Program received signal SIGSEGV, Segmentation fault.
0x00000000005caba0 in perf_env__arch_strerrno (env=0x0, err=110) at util/env.c:478
478 if (env->arch_strerrno == NULL)
(gdb) bt
#0 0x00000000005caba0 in perf_env__arch_strerrno (env=0x0, err=110) at util/env.c:478
#1 0x00000000004b75d2 in thread__dump_stats (ttrace=0x14f58f0, trace=0x7fffffffa5b0, fp=0x7ffff6ff74e0 <_IO_2_1_stderr_>) at builtin-trace.c:4673
#2 0x00000000004b78bf in trace__fprintf_thread (fp=0x7ffff6ff74e0 <_IO_2_1_stderr_>, thread=0x10fa0b0, trace=0x7fffffffa5b0) at builtin-trace.c:4708
#3 0x00000000004b7ad9 in trace__fprintf_thread_summary (trace=0x7fffffffa5b0, fp=0x7ffff6ff74e0 <_IO_2_1_stderr_>) at builtin-trace.c:4747
#4 0x00000000004b656e in trace__run (trace=0x7fffffffa5b0, argc=2, argv=0x7fffffffde60) at builtin-trace.c:4456
#5 0x00000000004ba43e in cmd_trace (argc=2, argv=0x7fffffffde60) at builtin-trace.c:5487
#6 0x00000000004c0414 in run_builtin (p=0xec3068 <commands+648>, argc=5, argv=0x7fffffffde60) at perf.c:351
#7 0x00000000004c06bb in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:404
#8 0x00000000004c0814 in run_argv (argcp=0x7fffffffdc4c, argv=0x7fffffffdc40) at perf.c:448
#9 0x00000000004c0b5d in main (argc=5, argv=0x7fffffffde60) at perf.c:560
(gdb)
After:
root@number:~# perf trace -a --errno-summary sleep 1
<SNIP>
pw-data-loop (2685), 1410 events, 16.0%
syscall calls errors total min avg max stddev
(msec) (msec) (msec) (msec) (%)
--------------- -------- ------ -------- --------- --------- --------- ------
epoll_wait 188 0 983.428 0.000 5.231 15.595 8.68%
ioctl 94 0 0.811 0.004 0.009 0.016 2.82%
read 188 0 0.322 0.001 0.002 0.006 5.15%
write 141 0 0.280 0.001 0.002 0.018 8.39%
timerfd_settime 94 0 0.138 0.001 0.001 0.007 6.47%
gnome-control-c (179406), 1848 events, 20.9%
syscall calls errors total min avg max stddev
(msec) (msec) (msec) (msec) (%)
--------------- -------- ------ -------- --------- --------- --------- ------
poll 222 0 959.577 0.000 4.322 21.414 11.40%
recvmsg 150 0 0.539 0.001 0.004 0.013 5.12%
write 300 0 0.442 0.001 0.001 0.007 3.29%
read 150 0 0.183 0.001 0.001 0.009 5.53%
getpid 102 0 0.101 0.000 0.001 0.008 7.82%
root@number:~#
Fixes: 54373b5d53 ("perf env: Introduce perf_env__arch_strerrno()")
Reported-by: Veronika Molnarova <vmolnaro@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Veronika Molnarova <vmolnaro@redhat.com>
Acked-by: Michael Petlan <mpetlan@redhat.com>
Tested-by: Michael Petlan <mpetlan@redhat.com>
Link: https://lore.kernel.org/r/Z0XffUgNSv_9OjOi@x1
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.