linux/tools/perf/util/pager.c
Namhyung Kim 4fd113b5ce perf report: Fix some option handling on --stdio
There's a bug that perf report sometimes ignore some options on --stdio
output.  This bug is triggered only if a related config variable is set.
For example, let's assume we have a following config file.

  $ cat ~/.perfconfig
  [call-graph]
    print-type = graph
  [hist]
    percentage = absolute

Then, following perf config will not honor some options.

  $ perf record -ag sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.199 MB perf.data (77 samples) ]

  $ perf report -g none --stdio
  # To display the perf.data header info, please use --header/--header-only options.
  #
  # Samples: 77  of event 'cycles'
  # Event count (approx.): 25425383
  #
  # Overhead  Command          Shared Object            Symbol
  # ........  ...............  .......................  ..............
  #
      16.34%  swapper          [kernel.vmlinux]         [k] intel_idle
                      |
                      ---intel_idle
                         cpuidle_enter_state
                         cpuidle_enter
                         cpu_startup_entry
   ...

With '-g none' option, it should not show callchains, but it still shows
callchains.  However it works as expected on --tui output.

Similarly, '--percentage relative' option is not work and still shows a
absolute percentage values.

Looking at the source, I found that those setting were overwritten by
config variables when setup_pager() called.  The setup_pager() is to
start a pager process so that it can manage long lines of output on the
stdio mode.  But as it calls the perf_config() after parsing arguments,
the settings were overwritten regardless of command line options.

The reason it calls perf_config() is to find the 'pager_program' which
might be set by a config variable, I guess.  However current perf code
does not provide the config variable for it, so it's just meaningless
IMHO.  Eliminating the call makes the option working as expected.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Taeung Song <treeze.taeung@gmail.com>
Link: http://lkml.kernel.org/r/1431529406-6762-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-14 10:05:22 -03:00

96 lines
1.8 KiB
C

#include "cache.h"
#include "run-command.h"
#include "sigchain.h"
/*
* This is split up from the rest of git so that we can do
* something different on Windows.
*/
static int spawned_pager;
static void pager_preexec(void)
{
/*
* Work around bug in "less" by not starting it until we
* have real input
*/
fd_set in;
FD_ZERO(&in);
FD_SET(0, &in);
select(1, &in, NULL, &in, NULL);
setenv("LESS", "FRSX", 0);
}
static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
static struct child_process pager_process;
static void wait_for_pager(void)
{
fflush(stdout);
fflush(stderr);
/* signal EOF to pager */
close(1);
close(2);
finish_command(&pager_process);
}
static void wait_for_pager_signal(int signo)
{
wait_for_pager();
sigchain_pop(signo);
raise(signo);
}
void setup_pager(void)
{
const char *pager = getenv("PERF_PAGER");
if (!isatty(1))
return;
if (!pager)
pager = getenv("PAGER");
if (!(pager || access("/usr/bin/pager", X_OK)))
pager = "/usr/bin/pager";
if (!(pager || access("/usr/bin/less", X_OK)))
pager = "/usr/bin/less";
if (!pager)
pager = "cat";
if (!*pager || !strcmp(pager, "cat"))
return;
spawned_pager = 1; /* means we are emitting to terminal */
/* spawn the pager */
pager_argv[2] = pager;
pager_process.argv = pager_argv;
pager_process.in = -1;
pager_process.preexec_cb = pager_preexec;
if (start_command(&pager_process))
return;
/* original process continues, but writes to the pipe */
dup2(pager_process.in, 1);
if (isatty(2))
dup2(pager_process.in, 2);
close(pager_process.in);
/* this makes sure that the parent terminates after the pager */
sigchain_push_common(wait_for_pager_signal);
atexit(wait_for_pager);
}
int pager_in_use(void)
{
const char *env;
if (spawned_pager)
return 1;
env = getenv("PERF_PAGER_IN_USE");
return env ? perf_config_bool("PERF_PAGER_IN_USE", env) : 0;
}