From: Jean-Michel Hautbois <jhautbois@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <dvhart@linux.intel.com>, linux-rt-users@vger.kernel.org
Subject: Re: Slub support with PREEMPT_RT ?
Date: Thu, 18 Nov 2010 09:59:31 +0100 [thread overview]
Message-ID: <AANLkTikV5Jykyv4+SBcJQqMvzMSUsXOUdXTQU5rOhcs_@mail.gmail.com> (raw)
In-Reply-To: <1290069601.2109.1295.camel@laptop>
2010/11/18 Peter Zijlstra <peterz@infradead.org>:
> On Wed, 2010-11-17 at 17:23 -0800, Darren Hart wrote:
>> On 11/17/2010 08:18 AM, Jean-Michel Hautbois wrote:
>> > Hi !
>> >
>> > I am wondering why SLUB isn't supported with PREEMPT_RT ?
>> > I cannot find any info on that except the fact it is not working yet.
>> > What do we have to do in order to support it ?
>>
>> Peter can answer this better than I can, but it has something to do with
>> all the local_bh_disable() calls not being compatible with the goals of
>> PREEMPT_RT - if I remember correctly.
>
> Nah, its slub doens't use the softirq crap. But its close, you have to
> iron out the per-cpu assumptions in the thing. I did a few slub-rt ports
> at various times but the thing kept changing too much and I gave up.
>
> I should probably do a new port and hope the thing is more stable now
> that the excitement is down or somesuch.
>
My real question is the impact of SLUB compared to SLAB on the
determinism of kmalloc usage and all caches.
I did some tests using SLUB instead of SLAB on a small (MPC5200 /
400Mhz / 16k i-cache and 16k d-cache), and slub seems to be better.
But I don't know if there is a possibility to tune SLAB in order to
get good results.
next prev parent reply other threads:[~2010-11-18 8:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-17 16:18 Slub support with PREEMPT_RT ? Jean-Michel Hautbois
2010-11-18 1:23 ` Darren Hart
2010-11-18 8:40 ` Peter Zijlstra
2010-11-18 8:59 ` Jean-Michel Hautbois [this message]
2010-11-18 11:04 ` Peter Zijlstra
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