Re: 'perf upgrade' (was: Re: [PATCH v9 00/11] Add support for JSON event files.)

From: Michael Ellerman <mpe@ellerman.id.au>
To: Ingo Molnar <mingo@kernel.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
	mingo@redhat.com, ak@linux.intel.com,
	Jiri Olsa <jolsa@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	peterz@infradead.org, namhyung@kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	Pekka Enberg <penberg@iki.fi>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: 'perf upgrade' (was: Re: [PATCH v9 00/11] Add support for JSON event files.)
Date: Wed, 15 Apr 2015 08:53:24 +1000	[thread overview]
Message-ID: <1429052004.10000.1.camel@ellerman.id.au> (raw)
In-Reply-To: <20150414125822.GA32761@gmail.com>

On Tue, 2015-04-14 at 14:58 +0200, Ingo Molnar wrote:
> * Michael Ellerman <mpe@ellerman.id.au> wrote:
> 
> > On Tue, 2015-04-14 at 10:55 +0200, Ingo Molnar wrote:
> > > * Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> wrote:
> > > 
> > > > This is another attempt to resurrect Andi Kleen's patchset so users
> > > > can specify perf events by their event names rather than raw codes.
> > > > 
> > > > This is a rebase of Andi Kleen's patchset from Jul 30, 2014[1] to 4.0.
> > > > (I fixed minor and not so minor conflicts).
> > > 
> > > So this series shows some progress, but instead of this limited 
> > > checkout ability I'd still prefer it if 'perf download' downloaded 
> > > the latest perf code itself and built it - it shouldn't be limited 
> > > to just a small subset of the perf source code!
> > 
> > Ingo, can you please stop blocking this? It's getting ridiculous.
> > 
> > We've been waiting over 8 months for this to go in.
> 
> We just merged a patch series that was first sent in 2013. Some things 
> take time to get right.

The first attempt to get symbolic event name support into perf was sent in
2010, that's FIVE years ago [1].

And what complicated feature are we asking for? The ability to map a human
readable name to a hex code, it has the complexity of a first year programming
assignment.

Variations have been submitted by IBM [1], by Facebook [2], now by Intel, and
Google have just given up and carry the libpfm4 patch in their perf tool [3].

Can we please just get this merged.

If you *then* want to add support for perf auto-updating that's fine, but don't
conflate the two.

cheers

[1]: https://lkml.org/lkml/2010/3/11/146
[2]: http://article.gmane.org/gmane.comp.linux.perfmon2.devel/2912
[3]: https://github.com/David-Levinthal/gooda/blob/master/gooda-analyzer/perf-patches/linux-v3.17/0001-perf-tools-add-support-for-libpfm4.patch