On Tue, 3 Dec 2019 12:35:09 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:
> In order to reuse the code, the function detecting the
> number of local CPU is moved from trace-cmd application to
> libtracecmd. The following new library API is introduced:
> int tracecmd_count_cpus(void);
>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
> ---
> include/trace-cmd/trace-cmd.h | 3 +++
> lib/trace-cmd/trace-util.c | 40 +++++++++++++++++++++++++++++
> tracecmd/include/trace-local.h | 2 --
> tracecmd/trace-agent.c | 2 +-
> tracecmd/trace-profile.c | 2 +-
> tracecmd/trace-record.c | 46 +++-------------------------------
> tracecmd/trace-stat.c | 4 +--
> 7 files changed, 50 insertions(+), 49 deletions(-)
>
> diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
> index 5287d23..5d4292e 100644
> --- a/include/trace-cmd/trace-cmd.h
> +++ b/include/trace-cmd/trace-cmd.h
> @@ -427,6 +427,9 @@ void tracecmd_plog(const char *fmt, ...);
> void tracecmd_plog_error(const char *fmt, ...);
> int tracecmd_set_logfile(char *logfile);
>
> +/* --- System --- */
> +int tracecmd_count_cpus(void);
> +
> /* --- Hack! --- */
> int tracecmd_blk_hack(struct tracecmd_input *handle);
>
> diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
> index 4c70d9a..e019dce 100644
> --- a/lib/trace-cmd/trace-util.c
> +++ b/lib/trace-cmd/trace-util.c
> @@ -1112,6 +1112,46 @@ int tracecmd_stack_tracer_status(int *status)
> return 1; /* full success */
> }
>
> +int tracecmd_count_cpus(void)
> +{
> + FILE *fp;
> + char buf[1024];
> + int cpus = 0;
> + char *pbuf;
> + size_t *pn;
> + size_t n;
> + int r;
> +
> + cpus = sysconf(_SC_NPROCESSORS_CONF);
> + if (cpus > 0)
> + return cpus;
> +
> + warning("sysconf could not determine number of CPUS");
As this is now a library function, probably should have a static
variable here:
static int once;
if (!once) {
once++;
warning("...");
}
No need to do more than one warning.
> +
> + /* Do the hack to figure out # of CPUS */
> + n = 1024;
> + pn = &n;
> + pbuf = buf;
> +
> + fp = fopen("/proc/cpuinfo", "r");
> + if (!fp)
> + die("Can not read cpuinfo");
Need to get rid of the die(). Could be in a separate patch.
Will also need to have the call sites check to see if the returned
number is negative, and fail there.
-- Steve
> +
> + while ((r = getline(&pbuf, pn, fp)) >= 0) {
> + char *p;
> +
> + if (strncmp(buf, "processor", 9) != 0)
> + continue;
> + for (p = buf+9; isspace(*p); p++)
> + ;
> + if (*p == ':')
> + cpus++;
> + }
> + fclose(fp);
> +
> + return cpus;
> +}
> +
> /*
> * tracecmd_write_file - Write in trace file
> * @file: Full name of the trace file.
> diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
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