linux-kernel - Re: [PATCH] perf tools: Dump callchain context marker names

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Message-ID: <aWas-QjeSE1iB_Zt@x1>
Date: Tue, 13 Jan 2026 17:37:13 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Namhyung Kim <namhyung@...nel.org>
Cc: James Clark <james.clark@...aro.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>, Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>, Leo Yan <leo.yan@....com>,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf tools: Dump callchain context marker names

On Fri, Jan 02, 2026 at 02:40:05PM -0800, Namhyung Kim wrote:
> Hi James,
> 
> Happy new year!
> 
> On Fri, Jan 02, 2026 at 12:15:43PM +0000, James Clark wrote:
> > These are hard to interpret in the raw output because they are printed
> > as hex but are defined in perf_event.h as decimal. Make it much easier
> > to read the raw callchains by just printing their names.
> > 
> > For example:
> > 
> >   $ perf report -D
> > 
> >   1798195372321 0x4638 [0xb0]: PERF_RECORD_SAMPLE(IP, 0x4002): 44922/44922: 0x7c8046dd3400 period: 120218 addr: 0
> >   ... FP chain: nr:12
> >   .....  0: fffffffffffffe00 (PERF_CONTEXT_USER)
> >   .....  1: 00007c8046dd3400
> >   .....  2: 00007c8046db86d3
> > 
> > Signed-off-by: James Clark <james.clark@...aro.org>
> > ---
> >  tools/perf/util/session.c | 25 +++++++++++++++++++++++--
> >  1 file changed, 23 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> > index 4236503c8f6c..e812f8954075 100644
> > --- a/tools/perf/util/session.c
> > +++ b/tools/perf/util/session.c
> > @@ -841,6 +841,26 @@ static void callchain__lbr_callstack_printf(struct perf_sample *sample)
> >  	}
> >  }
> >  
> > +static const char *callchain_context_str(u64 ip)
> > +{
> > +	switch (ip) {
> > +	case PERF_CONTEXT_HV:
> > +		return " (PERF_CONTEXT_HV)";
> > +	case PERF_CONTEXT_KERNEL:
> > +		return " (PERF_CONTEXT_KERNEL)";
> > +	case PERF_CONTEXT_USER:
> > +		return " (PERF_CONTEXT_USER)";
> 
> We now have PERF_CONTEXT_USER_DEFERRED too.

I ammended the patch with:

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index e812f89540755f31..65fa9bdff1b8cdf2 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -856,6 +856,8 @@ static const char *callchain_context_str(u64 ip)
                return " (PERF_CONTEXT_GUEST_KERNEL)";
        case PERF_CONTEXT_GUEST_USER:
                return " (PERF_CONTEXT_GUEST_USER)";
+       case PERF_CONTEXT_USER_DEFERRED:
+               return " (PERF_CONTEXT_USER_DEFERRED)";
        default:
                return "";
        }
⬢ [acme@...lbx perf-tools-next]$

And added a note about being Namhyung who made the suggestion, thanks.

- Arnaldo