From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [RFC] Some questions and an idea on SLUB/SLAB
Date: Sat, 9 Oct 2021 11:02:09 +0900 [thread overview]
Message-ID: <CAB=+i9R207ku5eN_W6LRokpuT-0VSYo6ao--8viUuhj2uuUcbQ@mail.gmail.com> (raw)
In-Reply-To: <YWDjZ+KlkV2wKShh@casper.infradead.org>
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On Sat, Oct 9, 2021, 9:34 AM Matthew Wilcox <willy@infradead.org> wrote:
> On Sat, Oct 09, 2021 at 12:19:03AM +0000, Hyeonggon Yoo wrote:
> > - Is there a reason that SLUB does not implement cache coloring?
> > it will help utilizing hardware cache. Especially in block layer,
> > they are literally *squeezing* its performance now.
>
> Have you tried turning off cache colouring in SLAB and seeing if
> performance changes? My impression is that it's useful for caches
> with low associativity (direct mapped / 2-way / 4-way), but loses
> its effectiveness for caches with higher associativity. For example,
> my laptop:
>
> L1 Data Cache: 48KB, 12-way associative, 64 byte line size
> L1 Instruction Cache: 32KB, 8-way associative, 64 byte line size
> L2 Unified Cache: 1280KB, 20-way associative, 64 byte line size
> L3 Unified Cache: 12288KB, 12-way associative, 64 byte line size
>
> I very much doubt that cache colouring is still useful for this machine.
>
And what was result on that benchmark?
How many cores on your processor?
And is it NUMA or UMA?
As I mentioned, color scheme is shared between cpus in same node.
I think we need to measure performqnce again after per-cpu coloring.
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next prev parent reply other threads:[~2021-10-09 2:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-09 0:19 Hyeonggon Yoo
2021-10-09 0:33 ` Matthew Wilcox
2021-10-09 0:40 ` Hyeonggon Yoo
2021-10-09 2:02 ` Hyeonggon Yoo [this message]
2021-10-09 11:45 ` Almost no difference Hyeonggon Yoo
2021-10-11 7:13 ` [RFC] Some questions and an idea on SLUB/SLAB Christoph Lameter
2021-10-13 3:44 ` Hyeonggon Yoo
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