From: Dave Chinner <david@fromorbit.com>
To: Waiman Long <waiman.long@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Andi Kleen <andi@firstfloor.org>,
Scott J Norton <scott.norton@hp.com>,
Douglas Hatch <doug.hatch@hp.com>
Subject: Re: [PATCH v2 1/3] lib/list_batch: A simple list insertion/deletion batching facility
Date: Sun, 7 Feb 2016 10:57:44 +1100 [thread overview]
Message-ID: <20160206235744.GI31407@dastard> (raw)
In-Reply-To: <56B2893C.4030609@hpe.com>
On Wed, Feb 03, 2016 at 06:11:56PM -0500, Waiman Long wrote:
> On 01/31/2016 07:47 PM, Dave Chinner wrote:
> >So at what point does simply replacing the list_head with a list_lru
> >become more efficient than this batch processing (i.e.
> >https://lkml.org/lkml/2015/3/10/660)? The list_lru isn't a great
> >fit for the inode list (doesn't need any of the special LRU/memcg
> >stuff https://lkml.org/lkml/2015/3/16/261) but it will tell us if,
> >like Ingo suggested, moving more towards a generic per-cpu list
> >would provide better overall performance...
>
> I will take a look at the list_lru patch to see if that help. As for
> the per-cpu list, I tried that and it didn't quite work out.
OK, see my last email as to why Andi's patch didn't change anything.
The list_lru implementation has a list per node, a lock per node,
and each item is placed on the list for the node it is physically
allocated from. Hence for local workloads, the list/lock that is
accessed for add/remove should be local to the node and hence should
reduce cache line contention mostly to within a single node.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2016-02-06 23:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-29 19:30 [PATCH v2 0/3] lib/list_batch: A simple list insertion/deletion batching facility Waiman Long
2016-01-29 19:30 ` [PATCH v2 1/3] " Waiman Long
2016-02-01 0:47 ` Dave Chinner
2016-02-03 23:11 ` Waiman Long
2016-02-06 23:57 ` Dave Chinner [this message]
2016-02-17 1:37 ` Waiman Long
2016-01-29 19:30 ` [PATCH v2 2/3] lib/list_batch, x86: Enable list insertion/deletion batching for x86 Waiman Long
2016-01-29 19:30 ` [PATCH v2 3/3] vfs: Enable list batching for the superblock's inode list Waiman Long
2016-01-30 8:35 ` Ingo Molnar
2016-02-01 17:45 ` Andi Kleen
2016-02-01 22:03 ` Waiman Long
2016-02-03 22:59 ` Waiman Long
2016-02-06 23:51 ` Dave Chinner
2016-02-01 21:44 ` Waiman Long
2016-02-01 0:04 ` Dave Chinner
2016-02-03 23:01 ` Waiman Long
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