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]

Message-ID: <1263831973.4283.622.camel@laptop>
Date:	Mon, 18 Jan 2010 17:26:13 +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 17:18 +0100, Frederic Weisbecker wrote:
> On Mon, Jan 18, 2010 at 03:56:41PM +0100, Peter Zijlstra wrote:
> > On Mon, 2010-01-18 at 15:45 +0100, Frederic Weisbecker wrote:
> > > 
> > > > > That requires to know in advance if we have hardware pmu
> > > > > in the list though (can be a flag in the group).
> > > > 
> > > > Good point, but your proposed hw_check_constraint() call needs to know
> > > > the exact same.
> > > 
> > > 
> > > True. Whatever model we use anyway, both implement the same idea.
> > 
> > Hmm, we seem to already have that problem (which would indicate another
> > bug in the hw-breakpoint stuff), how do you deal with
> > hw_perf_{enable,disable}() for the breakpoints?
> 
> 
> We don't have ordering constraints for breakpoints, only constraints
> on the number of available registers.
> 
> So we check the constraints when a breakpoint registers. The
> enable/disable then (is supposed to) always succeed on breakpoint
> pmu, except for flexible breakpoints that can make it or not,
> but no need to overwrite group scheduling for that.

hw_perf_{enable,disable} are unrelated to groups.

--
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/