From: Huang Shijie <shijie@os.amperecomputing.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Shijie Huang <shijie@amperemail.onmicrosoft.com>,
torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
akpm@linux-foundation.org, linux-mm@kvack.org,
song.bao.hua@hisilicon.com, linux-kernel@vger.kernel.org,
Frank Wang <zwang@amperecomputing.com>
Subject: Re: Is it possible to implement the per-node page cache for programs/libraries?
Date: Wed, 1 Sep 2021 13:30:45 +0000 [thread overview]
Message-ID: <YS+AhXJGsniaHTS4@hsj> (raw)
In-Reply-To: <YS7yjcqA6txFHd99@casper.infradead.org>
On Wed, Sep 01, 2021 at 04:25:01AM +0100, Matthew Wilcox wrote:
> On Wed, Sep 01, 2021 at 11:07:41AM +0800, Shijie Huang wrote:
> > In the NUMA, we only have one page cache for each file. For the
> > program/shared libraries, the
> > remote-access delays longer then the local-access.
> >
> > So, is it possible to implement the per-node page cache for
> > programs/libraries?
>
> At this point, we have no way to support text replication within a
> process. So what you're suggesting (if implemented) would work for
I created a glibc patch which can do the text replication within a process.
I will send to glibc maintainer later..
(it seems glibc does not use patches to maintain the code.)
> processes which limit themselves to a single node. That is, if you
> have a system with CPUs 0-3 on node 0 and CPUs 4-7 on node 1, a process
> which only works on node 0 or only works on node 1 will get text on the
> appropriate node.
>
> If there's a process which runs on both nodes 0 and 1, there's no support
> for per-node PGDs. So it will get a mix of pages from nodes 0 and 1,
I think we do not need the per-node PGDs.
One-PGD for one process is okay to me.
> and that doesn't necessarily seem like a big win. I haven't yet dived
> into how hard it would be to make mm->pgd a per-node allocation.
>
> I have been thinking about this a bit; one of our internal performance
> teams flagged the potential performance win to me a few months ago.
> I don't have a concrete design for text replication yet; there have been
> various attempts over the years, but none were particularly compelling.
>
> By the way, the degree of performance win varies between different CPUs,
> but it's measurable on all the systems we've tested on (from three
> different vendors).
Thank you for sharing this.
Thanks
Huang Shijie
next prev parent reply other threads:[~2021-09-01 5:32 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-01 3:07 Is it possible to implement the per-node page cache for programs/libraries? Shijie Huang
2021-09-01 2:09 ` Barry Song
2021-09-01 3:25 ` Matthew Wilcox
2021-09-01 13:30 ` Huang Shijie [this message]
2021-09-01 14:25 ` Huang Shijie
2021-09-01 11:32 ` Matthew Wilcox
2021-09-01 23:58 ` Matthew Wilcox
2021-09-02 0:15 ` Barry Song
2021-09-02 1:13 ` Linus Torvalds
2021-09-02 10:16 ` Huang Shijie
2021-09-02 3:25 ` Nicholas Piggin
2021-09-02 10:17 ` Matthew Wilcox
2021-09-03 7:10 ` Nicholas Piggin
2021-09-03 19:01 ` Matthew Wilcox
2021-09-03 19:08 ` Linus Torvalds
2021-09-06 9:56 ` Huang Shijie
2021-09-03 23:42 ` Nicholas Piggin
2021-09-01 4:55 ` Al Viro
2021-09-01 13:10 ` Huang Shijie
2021-09-01 17:24 ` Linus Torvalds
2021-09-01 17:29 ` Linus Torvalds
2021-09-01 22:56 ` Barry Song
2021-09-02 10:12 ` Huang Shijie
2021-09-02 10:08 ` Huang Shijie
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