linux-kernel - Re: [PATCH] perf_events: improve x86 event scheduling (v5)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 18 Jan 2010 15:37:01 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	Stephane Eranian <eranian@...gle.com>,
	linux-kernel@...r.kernel.org, mingo@...e.hu, paulus@...ba.org,
	davem@...emloft.net, perfmon2-devel@...ts.sf.net, eranian@...il.com
Subject: Re: [PATCH]  perf_events: improve x86 event scheduling (v5)

On Mon, 2010-01-18 at 15:20 +0100, Frederic Weisbecker wrote:
> 
> > Then there's still the question of having events of multiple hw pmus in
> > a single group, I'd be perfectly fine with saying that's not allowed,
> > what to others think?
> 
> 
> I guess we need that. It can be insteresting to couple
> hardware counters with memory accesses...or whatever.

That really depends on how easy it is to correlate events from the
various pmus. This case could indeed do that, but the core vs uncore
tihng is a lot less clear.

> Perf stat combines cache miss counting with page faults,
> cpu clock counters.

perf stat also doesn't use groups and it still works quite nicely.

> We shouldn't limit such possibilities for technical/cleanliness
> reasons. We should rather adapt.

Maybe, I'm not a very big fan of groups myself, but they are clearly
useful within a pmu, measuring cache misses through total-access for
example, but the use between pmus is questionable.

But sure, if we can do it without too much pain, that's fine.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/