linux-kernel - Re: [PATCH] cpuacct: VIRT_CPU_ACCOUNTING don't prevent percpu cputime count

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: <20090428075055.GD3825@in.ibm.com>
Date:	Tue, 28 Apr 2009 13:20:55 +0530
From:	Bharata B Rao <bharata@...ux.vnet.ibm.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Balaji Rao <balajirrao@...il.com>,
	Dhaval Giani <dhaval@...ux.vnet.ibm.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Balbir Singh <balbir@...ux.vnet.ibm.com>,
	Ingo Molnar <mingo@...e.hu>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	seto.hidetoshi@...fujitsu.com
Subject: Re: [PATCH] cpuacct: VIRT_CPU_ACCOUNTING don't prevent percpu
	cputime count

On Tue, Apr 28, 2009 at 04:38:51PM +0900, KOSAKI Motohiro wrote:
> > On Tue, Apr 28, 2009 at 03:53:32PM +0900, KOSAKI Motohiro wrote:
> 
> > BTW, did you observe any real problem with the percpu counter spinlock ?
> 
> No.
> I review percpu_counter() caller recently and it seems stragen usage.
> 

I should have phrased the question better ...

So have you found any performance degradation with any benchmarks/workloads
on archs which define VIRT_CPU_ACCOUNTING due to percpu_counter spinlock
being taken on every tick ? If the answer is no, don't you think we could
wait before making the kind of change you are proposing ?

Regards,
Bharata.
--
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/