linux-kernel - Re: [PATCH 0/3 v3] dcache: make it more scalable on large system

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: <51A66701.6050104@hp.com>
Date:	Wed, 29 May 2013 16:37:21 -0400
From:	Waiman Long <waiman.long@...com>
To:	Andi Kleen <andi@...stfloor.org>
CC:	Simo Sorce <simo@...hat.com>, Dave Chinner <david@...morbit.com>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Jeff Layton <jlayton@...hat.com>,
	Miklos Szeredi <mszeredi@...e.cz>, Ian Kent <raven@...maw.net>,
	Sage Weil <sage@...tank.com>, Steve French <sfrench@...ba.org>,
	Trond Myklebust <Trond.Myklebust@...app.com>,
	Eric Paris <eparis@...hat.com>, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, autofs@...r.kernel.org,
	ceph-devel@...r.kernel.org, linux-cifs@...r.kernel.org,
	linux-nfs@...r.kernel.org,
	"Chandramouleeswaran, Aswin" <aswin@...com>,
	"Norton, Scott J" <scott.norton@...com>
Subject: Re: [PATCH 0/3 v3] dcache: make it more scalable on large system

On 05/29/2013 12:56 PM, Andi Kleen wrote:
> On Wed, May 29, 2013 at 12:18:09PM -0400, Simo Sorce wrote:
>> To be honest a workload base on /etc/passwd or /etc/group is completely
>> artificial, in actual usage, if you really have  such access you use
>> nscd or sssd with their shared memory caches to completely remove most
>> of the file access.
> I don't fully agree at this point. A lot of things can be tuned away,
> but in practice we want things to perform well out of the box without
> needing all kinds of magic tuning that only
>
> Also this is just normal file access, nothing special about it.
> It simply has to scale. For all kinds of workloads.
>
> And it does, just d_path messes it up.

Just for clarification, the AIM7 workload is not affected by the current 
d_path() code, they are speed-limited by the lock contention in the 
dcache reference counting code. However, both the d_path() change and  
the dentry reference counting change are needed to to eliminate the 
overhead introduced by the use of the perf-record command.

Regards,
Longman
--
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/