linux-kernel - Re: Perf tests for hw events

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]

Message-ID: <20150122170804.GG12079@codeblueprint.co.uk>
Date:	Thu, 22 Jan 2015 17:08:04 +0000
From:	Matt Fleming <matt@...eblueprint.co.uk>
To:	Jiri Olsa <jolsa@...hat.com>
Cc:	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Jiri Olsa <jolsa@...nel.org>, linux-kernel@...r.kernel.org,
	Peter Zijlstra <peterz@...radead.org>,
	Andi Kleen <andi@...stfloor.org>,
	Vince Weaver <vince@...ter.net>,
	Vikas Shivappa <vikas.shivappa@...ux.intel.com>,
	Kanaka Juvva <kanaka.d.juvva@...el.com>,
	Ingo Molnar <mingo@...nel.org>
Subject: Re: Perf tests for hw events

On Thu, 22 Jan, at 01:56:59PM, Jiri Olsa wrote:
> On Thu, Jan 22, 2015 at 12:40:14PM +0000, Matt Fleming wrote:
> > Folks,
> > 
> > In the process of writing perf support for Intel's Cache QoS Monitoring
> > feature [0] I've had to write my own userland tests to drive tools/perf
> > and indirectly the kernel internals. I'm now getting requests for these
> > tests from various people and it occurs to me that they should probably
> > live in the kernel tree.
> > 
> > The tests I've got do a couple of things like setting up a perf_event
> > cgroup and assigning enough tasks to trigger the RMID recycling code in
> > the CQM driver, ensuring that we can run multiple events simultaneously
> > (that the event scheduling/rotation code works), etc.
> > 
> > Does anything like this already exist for hw events? I couldn't find
> > anything specific to hw events from snooping around in tools/perf/tests. 
> 
> that's the only place for this kind of stuff.. and AFAIK we use
> just some basic HW events like cycles, or software events
 
OK cool. I just wanted confirmation that tools/perf/tests was the best
place for these tests.

> > We should only test those hw events that are present on a user's
> > machine; there's no sense in emulating things.
> 
> agreed.. I remember we were discussing with Arnaldo the strengthening
> of the test framework.. so it would detect what tests are runable
> under current machine and priviledge
> 
> IIRC we already have some CPU detection support:
>   int __attribute__ ((weak)) get_cpuid(char *buffer, size_t sz);

Aha, excellent. I hadn't noticed this. It should be possible to build
something on top of this.

-- 
Matt Fleming, Intel Open Source Technology Center
--
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/