lkml.org 
[lkml]   [2008]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Scalability requirements for sysv ipc (+namespaces broken with SEM_UNDO)
Mike Galbraith wrote:
> On Sat, 2008-03-22 at 20:08 +0100, Manfred Spraul wrote:
>
>
>> just the normal performance of 2.6.25-rc3 is abyssimal, 55 to 60% slower
>> than 2.6.18.8:
>>
>
> After manually reverting 3e148c79938aa39035669c1cfa3ff60722134535,
> 2.6.25.git scaled linearly
We can't just revert that patch: with IDR, a global lock is mandatory :-(
We must either revert the whole idea of using IDR or live with the
reduced scalability.

Actually, there are further bugs: the undo structures are not
namespace-aware, thus semop with SEM_UNDO, unshare, create new array
with same id, but more semaphores, another semop with SEM_UNDO will
corrupt kernel memory :-(
I'll try to clean up the bugs first, then I'll look at the scalability
again.

--
Manfred


\
 
 \ /
  Last update: 2008-03-30 16:15    [W:0.122 / U:0.824 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site