linux-kernel - Re: [PATCH 1/4] perf, x86: Add Intel Nehalem/Westmere uncore pmu

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: <1309871625.2381.9.camel@localhost>
Date:	Tue, 05 Jul 2011 21:13:45 +0800
From:	Lin Ming <ming.m.lin@...el.com>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:	Andi Kleen <andi@...stfloor.org>, Ingo Molnar <mingo@...e.hu>,
	Stephane Eranian <eranian@...gle.com>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/4] perf, x86: Add Intel Nehalem/Westmere uncore pmu

On Tue, 2011-07-05 at 20:56 +0800, Peter Zijlstra wrote:
> On Tue, 2011-07-05 at 20:48 +0800, Lin Ming wrote:
> > On Tue, 2011-07-05 at 19:22 +0800, Peter Zijlstra wrote:
> > > On Mon, 2011-07-04 at 23:57 +0200, Andi Kleen wrote:
> > > > > > There are no NMIs without sampling, so at least the comment seems bogus.
> > > > > > Perhaps the code could be a bit simplified now without atomics.
> > > > > 
> > > > > I'm not sure if uncore PMU interrupt need to be enabled for counting
> > > > > only. What do you think?
> > > > 
> > > > Only for overflow handling to accumulate into a larger counter, but it doesn't 
> > > > need to be an NMI for that.
> > > 
> > > Uncore is hooked into the regular PMI, and since we wire that to the NMI
> > > the uncore will always be NMI too.
> > > 
> > > >   But it's not strictly required I would say, 
> > > > 44(?) bits are probably enough for near all use cases.
> > > 
> > > 44bits is in the hours range for pure cycle counts, which is so-so. I
> > > bet you're going to be very annoyed when you find your counters are
> > > wrecked after your 5 hour test run finishes.
> > 
> > I'll add the interrupt handling code back.
> 
> Does it work? The problem was with the hardware being iffy.

It may work on SandyBridge.

--
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/