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From: Manfred Spraul <manfred@colorfullife.com>
To: Mike Galbraith <efault@gmx.de>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
paulmck@linux.vnet.ibm.com, Nadia Derbey <Nadia.Derbey@bull.net>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Pavel Emelianov <xemul@openvz.org>
Subject: Re: Scalability requirements for sysv ipc (+namespaces broken with SEM_UNDO)
Date: Sun, 30 Mar 2008 16:12:18 +0200 [thread overview]
Message-ID: <47EF9FC2.3050901@colorfullife.com> (raw)
In-Reply-To: <1206460206.4414.21.camel@marge.simson.net>
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
next prev parent reply other threads:[~2008-03-30 14:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-21 9:41 Scalability requirements for sysv ipc (was: ipc: store ipcs into IDRs) Manfred Spraul
2008-03-21 12:45 ` Nadia Derbey
2008-03-21 13:33 ` Scalability requirements for sysv ipc Manfred Spraul
2008-03-21 14:13 ` Paul E. McKenney
2008-03-21 16:08 ` Manfred Spraul
2008-03-22 5:43 ` Mike Galbraith
2008-03-22 10:10 ` Manfred Spraul
2008-03-22 11:53 ` Mike Galbraith
2008-03-22 14:22 ` Manfred Spraul
2008-03-22 19:08 ` Manfred Spraul
2008-03-25 15:50 ` Mike Galbraith
2008-03-25 16:13 ` Peter Zijlstra
2008-03-25 18:31 ` Mike Galbraith
2008-03-26 6:18 ` Mike Galbraith
2008-03-30 14:12 ` Manfred Spraul [this message]
2008-03-30 15:21 ` Scalability requirements for sysv ipc (+namespaces broken with SEM_UNDO) David Newall
2008-03-30 17:18 ` Mike Galbraith
2008-04-04 14:59 ` Nadia Derbey
2008-04-04 15:03 ` Nadia Derbey
2008-03-22 19:35 ` Scalability requirements for sysv ipc Mike Galbraith
2008-03-23 6:38 ` Manfred Spraul
2008-03-23 7:15 ` Mike Galbraith
2008-03-23 7:08 ` Mike Galbraith
2008-03-23 7:20 ` Mike Galbraith
2008-03-27 22:29 ` Bill Davidsen
2008-03-28 9:49 ` Manfred Spraul
2008-03-25 16:00 ` Nadia Derbey
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