From: Peter Zijlstra <peterz@infradead.org>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org,
Josh Poimboeuf <jpoimboe@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Jiri Olsa <jolsa@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Stephane Eranian <eranian@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [perf] perf_event.h ABI visibility question
Date: Mon, 27 Aug 2018 09:52:46 +0200 [thread overview]
Message-ID: <20180827075246.GX24124@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.21.1808241706120.12717@macbook-air>
On Fri, Aug 24, 2018 at 05:09:27PM -0400, Vince Weaver wrote:
> On Fri, 24 Aug 2018, Peter Zijlstra wrote:
>
> > > +++ b/include/uapi/linux/perf_event.h
> > > @@ -143,6 +143,8 @@ enum perf_event_sample_format {
> > > PERF_SAMPLE_PHYS_ADDR = 1U << 19,
> > >
> > > PERF_SAMPLE_MAX = 1U << 20, /* non-ABI */
> > > +
> > > + __PERF_SAMPLE_CALLCHAIN_EARLY = 1ULL << 63,
> > > };
> > >
> >
> > Hurphm.. visible yes, but as you say, also quite useless. Does it really
> > make sense to document that?
>
> Well, it should probably be documented either in the manpage or else in
> perf_event.h (even if it's just "internal use, don't use") as we can't
> really expect people to download a git tree and do a git-blame to try to
> figure out what this mysterious field is all about.
Something like so then?
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index eeb787b1c53c..f35eb72739c0 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -144,7 +144,7 @@ enum perf_event_sample_format {
PERF_SAMPLE_MAX = 1U << 20, /* non-ABI */
- __PERF_SAMPLE_CALLCHAIN_EARLY = 1ULL << 63,
+ __PERF_SAMPLE_CALLCHAIN_EARLY = 1ULL << 63, /* non-ABI; internal use */
};
/*
> Also, this change increased the size of the enum from 32 to 64 bits on
> 32-bit machines, though that only really matters if the user is doing
> something really weird with enum variables.
Yeah, since the target variable is a u64 I really can't be bothered with
that.
next prev parent reply other threads:[~2018-08-27 7:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-23 18:25 [perf] perf_event.h ABI visibility question Vince Weaver
2018-08-24 8:50 ` Peter Zijlstra
2018-08-24 21:09 ` Vince Weaver
2018-08-27 7:52 ` Peter Zijlstra [this message]
2018-08-28 17:51 ` Vince Weaver
2018-08-29 12:13 ` Peter Zijlstra
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