From: Eric Dumazet <eric.dumazet@gmail.com>
To: Ezequiel Garcia <elezegarcia@gmail.com>
Cc: Tim Bird <tim.bird@am.sony.com>,
David Rientjes <rientjes@google.com>,
Andi Kleen <andi@firstfloor.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"celinux-dev@lists.celinuxforum.org"
<celinux-dev@lists.celinuxforum.org>
Subject: Re: [Q] Default SLAB allocator
Date: Tue, 16 Oct 2012 21:16:08 +0200 [thread overview]
Message-ID: <1350414968.3954.1427.camel@edumazet-glaptop> (raw)
In-Reply-To: <CALF0-+VLVqy_uE63_jL83qh8MqBQAE3vYLRX1mRQURZ4a1M20g@mail.gmail.com>
On Tue, 2012-10-16 at 15:27 -0300, Ezequiel Garcia wrote:
> Yes, we have some numbers:
>
> http://elinux.org/Kernel_dynamic_memory_analysis#Kmalloc_objects
>
> Are they too informal? I can add some details...
>
> They've been measured on a **very** minimal setup, almost every option
> is stripped out, except from initramfs, sysfs, and trace.
>
> On this scenario, strings allocated for file names and directories
> created by sysfs
> are quite noticeable, being 4-16 bytes, and produce a lot of fragmentation from
> that 32 byte cache at SLAB.
>
> Is an option to enable small caches on SLUB and SLAB worth it?
Random small web server :
# free
total used free shared buffers cached
Mem: 7884536 5412572 2471964 0 155440 1803340
-/+ buffers/cache: 3453792 4430744
Swap: 2438140 51164 2386976
# grep Slab /proc/meminfo
Slab: 351592 kB
# egrep "kmalloc-32|kmalloc-16|kmalloc-8" /proc/slabinfo
kmalloc-32 11332 12544 32 128 1 : tunables 0 0 0 : slabdata 98 98 0
kmalloc-16 5888 5888 16 256 1 : tunables 0 0 0 : slabdata 23 23 0
kmalloc-8 76563 82432 8 512 1 : tunables 0 0 0 : slabdata 161 161 0
Really, some waste on these small objects is pure noise on SMP hosts.
(Waste on bigger objects is probably more important by orders of magnitude)
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next prev parent reply other threads:[~2012-10-16 19:16 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-11 14:19 Ezequiel Garcia
2012-10-11 22:42 ` Andi Kleen
2012-10-11 22:59 ` David Rientjes
2012-10-11 23:10 ` Andi Kleen
2012-10-12 12:07 ` Ezequiel Garcia
2012-10-13 9:54 ` David Rientjes
2012-10-13 12:44 ` Ezequiel Garcia
2012-10-16 0:46 ` David Rientjes
2012-10-16 12:35 ` Ezequiel Garcia
2012-10-16 12:56 ` Eric Dumazet
2012-10-16 18:07 ` Tim Bird
2012-10-16 18:27 ` Ezequiel Garcia
2012-10-16 18:44 ` Tim Bird
2012-10-16 18:49 ` Ezequiel Garcia
2012-10-16 19:16 ` Eric Dumazet [this message]
2012-10-17 18:45 ` Tim Bird
2012-10-17 19:13 ` Eric Dumazet
2012-10-17 19:20 ` Shentino
2012-10-17 20:33 ` Tim Bird
2012-10-18 0:46 ` Shentino
2012-10-17 20:58 ` Tim Bird
2012-10-17 21:05 ` Ezequiel Garcia
2012-10-16 18:36 ` Ezequiel Garcia
2012-10-16 18:54 ` Christoph Lameter
2012-10-13 9:51 ` David Rientjes
2012-10-13 15:10 ` Eric Dumazet
2012-10-16 1:28 ` JoonSoo Kim
2012-10-16 7:23 ` Eric Dumazet
2012-10-19 0:03 ` JoonSoo Kim
2012-10-19 7:01 ` Eric Dumazet
2012-10-16 0:45 ` David Rientjes
2012-10-16 18:53 ` Christoph Lameter
2012-10-16 19:02 ` Christoph Lameter
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