lkml.org 
[lkml]   [2008]   [Nov]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 0/6] fs: Scalability of sockets/pipes allocation/deallocation on SMP
On Thu, 27 Nov 2008, Eric Dumazet wrote:

> with slub_min_objects=45 :
>
> # cat /sys/kernel/slab/filp/order
> 2
> # time ./socket8
> real 0m1.652s
> user 0m0.694s
> sys 0m12.367s

That may be a good value. How many processor do you have? Look at
calculate_order() in mm/slub.c:

if (!min_objects)
min_objects = 4 * (fls(nr_cpu_ids) + 1);

We couild increase the scaling factor there or start
with a mininum of 20 objects?


Try

min_objects = 20 + 4 * (fls(nr_cpu_ids) + 1);

> I would say slub_min_objects=45 is the optimal value on 32bit arches to
> get acceptable performance on this workload (order=2 for filp kmem_cache)
>
> Note : SLAB here is disastrous, but you already knew that :)

Its good though to have examples where the queue management gets in the
way of performance.


\
 
 \ /
  Last update: 2008-11-27 15:49    [W:0.170 / U:0.104 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site