From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
brouer@redhat.com
Subject: Re: [PATCH V2 6/6] slub: add support for kmem_cache_debug in bulk calls
Date: Wed, 17 Jun 2015 17:24:13 +0200 [thread overview]
Message-ID: <20150617172413.5c111a63@redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1506171006020.31991@east.gentwo.org>
On Wed, 17 Jun 2015 10:08:28 -0500 (CDT) Christoph Lameter <cl@linux.com> wrote:
> > Per request of Joonsoo Kim adding kmem debug support.
>
> > bulk- PREVIOUS - THIS-PATCH
> > 1 - 43 cycles(tsc) 10.811 ns - 44 cycles(tsc) 11.236 ns improved -2.3%
> > 2 - 27 cycles(tsc) 6.867 ns - 28 cycles(tsc) 7.019 ns improved -3.7%
> > 3 - 21 cycles(tsc) 5.496 ns - 22 cycles(tsc) 5.526 ns improved -4.8%
> > 4 - 24 cycles(tsc) 6.038 ns - 19 cycles(tsc) 4.786 ns improved 20.8%
> > 8 - 17 cycles(tsc) 4.280 ns - 18 cycles(tsc) 4.572 ns improved -5.9%
> > 16 - 17 cycles(tsc) 4.483 ns - 18 cycles(tsc) 4.658 ns improved -5.9%
> > 30 - 18 cycles(tsc) 4.531 ns - 18 cycles(tsc) 4.568 ns improved 0.0%
> > 32 - 58 cycles(tsc) 14.586 ns - 65 cycles(tsc) 16.454 ns improved -12.1%
> > 34 - 53 cycles(tsc) 13.391 ns - 63 cycles(tsc) 15.932 ns improved -18.9%
> > 48 - 65 cycles(tsc) 16.268 ns - 50 cycles(tsc) 12.506 ns improved 23.1%
> > 64 - 53 cycles(tsc) 13.440 ns - 63 cycles(tsc) 15.929 ns improved -18.9%
> > 128 - 79 cycles(tsc) 19.899 ns - 86 cycles(tsc) 21.583 ns improved -8.9%
> > 158 - 90 cycles(tsc) 22.732 ns - 90 cycles(tsc) 22.552 ns improved 0.0%
> > 250 - 95 cycles(tsc) 23.916 ns - 98 cycles(tsc) 24.589 ns improved -3.2%
>
> Hmmm.... Can we afford these regressions?
Do notice the "regression" is mostly within 1 cycle. Which I would not
call a regression, given the accuracy of these measurements.
The page-border cases 32,34,48,64 cannot be use to assess this.
We could look at the assembler code, to see if we can spot the extra
instruction that does not get optimized away.
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Sr. Network Kernel Developer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
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prev parent reply other threads:[~2015-06-17 15:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-17 14:26 [PATCH V2 0/6] slub: bulk alloc and free for slub allocator Jesper Dangaard Brouer
2015-06-17 14:27 ` [PATCH V2 1/6] slub: fix spelling succedd to succeed Jesper Dangaard Brouer
2015-06-17 14:27 ` [PATCH V2 2/6] slab: infrastructure for bulk object allocation and freeing Jesper Dangaard Brouer
2015-06-17 14:28 ` [PATCH V2 3/6] slub bulk alloc: extract objects from the per cpu slab Jesper Dangaard Brouer
2015-06-17 14:28 ` [PATCH V2 4/6] slub: improve bulk alloc strategy Jesper Dangaard Brouer
2015-06-17 14:29 ` [PATCH V2 5/6] slub: initial bulk free implementation Jesper Dangaard Brouer
2015-06-17 14:29 ` [PATCH V2 6/6] slub: add support for kmem_cache_debug in bulk calls Jesper Dangaard Brouer
2015-06-17 15:08 ` Christoph Lameter
2015-06-17 15:24 ` Jesper Dangaard Brouer [this message]
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