Messages in this thread | | | Date | Wed, 16 Oct 2019 08:13:33 +0800 | From | Changbin Du <> | Subject | Re: [PATCH v4 2/2] perf: add support for logging debug messages to file |
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On Mon, Oct 14, 2019 at 05:29:53PM +0200, Jiri Olsa wrote: > 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.du@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 > Acorrding to my test, some messages are lost after ctrl-c without flusing. So I think it is buffered by libc?
> > - 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 > yes, it should be mentioned.
> > + > > + 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? > Yes, because we will append new log to existing one. So we'd beeter put a margin there.
> jirka > > > + set_log_output(f); > > + } else { > > fprintf(stderr, "unkown debug option '%s'\n", opt); > > free(dstr); > > return -1; > > -- > > 2.20.1 > >
-- Cheers, Changbin Du
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