linux-kernel - Re: [PATCH] perf report: Output non-zero offset for decompressed records

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Message-ID: <YVqn/FZ544RAV6Mq@krava>
Date:   Mon, 4 Oct 2021 09:06:36 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     "Bayduraev, Alexey V" <alexey.v.bayduraev@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Alexander Antonov <alexander.antonov@...ux.intel.com>,
        Alexei Budankov <abudankov@...wei.com>,
        Riccardo Mancini <rickyman7@...il.com>
Subject: Re: [PATCH] perf report: Output non-zero offset for decompressed
 records

On Mon, Oct 04, 2021 at 10:00:52AM +0300, Bayduraev, Alexey V wrote:
> 
> On 04.10.2021 9:42, Jiri Olsa wrote:
> > On Wed, Sep 29, 2021 at 12:14:45PM +0300, Alexey Bayduraev wrote:
> >> Print offset of PERF_RECORD_COMPRESSED record instead of zero for
> >> decompressed records in raw trace dump (-D option of perf-report):
> >>
> >> 0x17cf08 [0x28]: event: 9
> >>
> >> instead of:
> >>
> >> 0 [0x28]: event: 9
> >>
> >> The fix is not critical, because currently file_pos for compressed
> >> events is used in perf_session__process_event only to show offsets
> >> in the raw dump.
> > 
> > hi,
> > I don't mind the change just curious, because I see also:
> > 
> >   perf_session__process_event
> >     perf_session__process_user_event
> >       lseek(fd, file_offset, ...
> > 
> > which is not raw dump as the comment suggests
> 
> Hi,
> 
> Yes, but this "lseek" only works for user events, whereas the 
> PERF_RECORD_COMPRESSED record shouln't contain such events.
> Currently, the PERF_RECORD_COMPRESSED container can only pack
> kernel events. 

Acked-by: Jiri Olsa <jolsa@...hat.com>

thanks,
jirka

> 
> Regards,
> Alexey
> 
> > 
> > thanks,
> > jirka
> > 
> >>
> >> This patch was separated from patchset:
> >> https://lore.kernel.org/lkml/cover.1629186429.git.alexey.v.bayduraev@linux.intel.com/
> >> and was already rewieved.
> >>
> >> Acked-by: Namhyung Kim <namhyung@...nel.org>
> >> Acked-by: Andi Kleen <ak@...ux.intel.com>
> >> Reviewed-by: Riccardo Mancini <rickyman7@...il.com>
> >> Tested-by: Riccardo Mancini <rickyman7@...il.com>
> >> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>
> >> ---
> >>  tools/perf/util/session.c | 4 ++--
> >>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> >> index 069c2cfdd3be..352f16076e01 100644
> >> --- a/tools/perf/util/session.c
> >> +++ b/tools/perf/util/session.c
> >> @@ -2116,7 +2116,7 @@ fetch_decomp_event(u64 head, size_t mmap_size, char *buf, bool needs_swap)
> >>  static int __perf_session__process_decomp_events(struct perf_session *session)
> >>  {
> >>  	s64 skip;
> >> -	u64 size, file_pos = 0;
> >> +	u64 size;
> >>  	struct decomp *decomp = session->decomp_last;
> >>  
> >>  	if (!decomp)
> >> @@ -2132,7 +2132,7 @@ static int __perf_session__process_decomp_events(struct perf_session *session)
> >>  		size = event->header.size;
> >>  
> >>  		if (size < sizeof(struct perf_event_header) ||
> >> -		    (skip = perf_session__process_event(session, event, file_pos)) < 0) {
> >> +		    (skip = perf_session__process_event(session, event, decomp->file_pos)) < 0) {
> >>  			pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
> >>  				decomp->file_pos + decomp->head, event->header.size, event->header.type);
> >>  			return -EINVAL;
> >> -- 
> >> 2.19.0
> >>
> > 
>