On Tue, Oct 08, 2019 at 08:35:54PM +0800, Changbin Du wrote:
> When in TUI mode, it is impossible to show all the debug messages to
> console. This make it hard to debug perf issues using debug messages.
> This patch adds support for logging debug messages to file to resolve
> this problem.
>
> The usage is:
> perf -debug verbose=2,file=~/perf.log COMMAND
>
> Signed-off-by: Changbin Du <changbin...@gmail.com>
>
> --
> v4: fix another segfault.
> v3: fix a segfault issue.
hi,
no crash this time ;-) some questions below
> ---
> tools/perf/Documentation/perf.txt | 15 ++++++-----
> tools/perf/util/debug.c | 44 ++++++++++++++++++++++++++++---
> 2 files changed, 49 insertions(+), 10 deletions(-)
>
> diff --git a/tools/perf/Documentation/perf.txt
> b/tools/perf/Documentation/perf.txt
> index c05a94b2488e..a6b19661e5c3 100644
> --- a/tools/perf/Documentation/perf.txt
> +++ b/tools/perf/Documentation/perf.txt
> @@ -16,14 +16,17 @@ OPTIONS
> Setup debug variable (see list below) in value
> range (0, 10). Use like:
> --debug verbose # sets verbose = 1
> - --debug verbose=2 # sets verbose = 2
> + --debug verbose=2,file=~/perf.log
> + # sets verbose = 2 and save log to file
>
> List of debug variables allowed to set:
> - verbose=level - general debug messages
> - ordered-events=level - ordered events object debug messages
> - data-convert=level - data convert command debug messages
> - stderr - write debug output (option -v) to stderr
> - in browser mode
> + verbose=level - general debug messages
> + ordered-events=level - ordered events object debug messages
> + data-convert=level - data convert command debug messages
> + stderr - write debug output (option -v) to stderr
> + in browser mode
> + file=path - write debug output to log file (stderr and
> + file options are exclusive)
>
> --buildid-dir::
> Setup buildid cache directory. It has higher priority than
> diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
> index df82ad9cd16d..5cc2479d63ea 100644
> --- a/tools/perf/util/debug.c
> +++ b/tools/perf/util/debug.c
> @@ -6,6 +6,7 @@
> #include <stdarg.h>
> #include <stdio.h>
> #include <stdlib.h>
> +#include <errno.h>
> #include <sys/wait.h>
> #include <api/debug.h>
> #include <linux/kernel.h>
> @@ -26,7 +27,7 @@
> int verbose;
> bool dump_trace = false, quiet = false;
> int debug_ordered_events;
> -static bool redirect_to_stderr;
> +static FILE *log_file;
> int debug_data_convert;
>
> int veprintf(int level, int var, const char *fmt, va_list args)
> @@ -34,8 +35,10 @@ int veprintf(int level, int var, const char *fmt, va_list
> args)
> int ret = 0;
>
> if (var >= level) {
> - if (use_browser >= 1 && !redirect_to_stderr)
> + if (use_browser >= 1 && !log_file)
> ui_helpline__vshow(fmt, args);
> + else if (log_file)
> + ret = vfprintf(log_file, fmt, args);
> else
> ret = vfprintf(stderr, fmt, args);
> }
> @@ -197,6 +200,24 @@ static int str2loglevel(const char *vstr)
> return v;
> }
>
> +static void flush_log(void)
> +{
> + if (log_file)
> + fflush(log_file);
> +}
> +
> +static void set_log_output(FILE *f)
> +{
> + if (f == log_file)
> + return;
> +
> + if (log_file && log_file != stderr)
> + fclose(log_file);
> +
> + log_file = f;
> + atexit(flush_log);
> +}
> +
> int perf_debug_option(const char *str)
> {
> char *sep, *vstr;
> @@ -218,8 +239,23 @@ int perf_debug_option(const char *str)
> else if (!strcmp(opt, "data-convert"))
> debug_data_convert = str2loglevel(vstr);
> else if (!strcmp(opt, "stderr"))
> - redirect_to_stderr = true;
do you ned to fflush stderr? I thought it's unbuffered
> - else {
> + set_log_output(stderr);
> + else if (!strcmp(opt, "file")) {
> + FILE *f;
> +
> + if (!vstr)
> + vstr = (char *)"perf.log";
you did not mention in doc that perf.log is default
> +
> + f = fopen(vstr, "a");
> + if (!f) {
> + pr_err("Can not create log file: %s\n",
> + strerror(errno));
> + free(dstr);
> + return -1;
> + }
> + fprintf(f, "\n===========perf log===========\n");
is this necessary?
jirka
> + set_log_output(f);
> + } else {
> fprintf(stderr, "unkown debug option '%s'\n", opt);
> free(dstr);
> return -1;
> --
> 2.20.1
>
