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Message-Id: <D2301275-8653-41CB-BADB-E927CF00BDB0@fastmail.fm>
Date: Sat, 30 Jul 2011 06:39:34 +1000
From: Greg Banks <gnb@...tmail.fm>
To: "J. Bruce Fields" <bfields@...ldses.org>
Cc: Eric Dumazet <eric.dumazet@...il.com>,
Trond Myklebust <Trond.Myklebust@...app.com>,
Neil Brown <neilb@...e.de>, David Miller <davem@...emloft.net>,
"linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
netdev <netdev@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
"bmarson@...hat.com" <bmarson@...hat.com>
Subject: Re: [PATCH] sunrpc: use better NUMA affinities
Sent from my iPhone
On 30/07/2011, at 4:08, "J. Bruce Fields" <bfields@...ldses.org> wrote:
> On Fri, Jul 29, 2011 at 08:02:05PM +0200, Eric Dumazet wrote:
>> Le vendredi 29 juillet 2011 à 12:42 -0400, J. Bruce Fields a écri
>> t :
>>> On Thu, Jul 28, 2011 at 08:04:09PM +0200, Eric Dumazet wrote:
>>>> Use NUMA aware allocations to reduce latencies and increase
>>>> throughput.
>>>>
>>>> sunrpc kthreads can use kthread_create_on_node() if pool_mode is
>>>> "percpu" or "pernode", and svc_prepare_thread()/svc_init_buffer()
>>>> can
>>>> also take into account NUMA node affinity for memory allocations.
>>> ...
>>>> @@ -662,14 +675,16 @@ svc_set_num_threads(struct svc_serv *serv,
>>>> struct svc_pool *pool, int nrservs)
>>>> nrservs--;
>>>> chosen_pool = choose_pool(serv, pool, &state);
>>>>
>>>> - rqstp = svc_prepare_thread(serv, chosen_pool);
>>>> + node = svc_pool_map_get_node(chosen_pool->sp_id);
>>>> + rqstp = svc_prepare_thread(serv, chosen_pool, node);
>>>
>>> The only correct value for the third argument there is
>>> svc_pool_map_get_node(chosen_pool->sp_id), so let's have
>>> svc_prepare_thread() call that itself.
>>>
>>
>> I have no idea of what you mean ;)
>>
>> I need 'node' for the following kthread_create_on_node()
>
> Doh, of course--apologies.
>
>>> Seems OK otherwise.
>>>
>>> Any suggestions on how we should test this?
>>
>> I did tests on my machine, seems good.
>>
>> I checked that stacks were now correct using :
>> "echo t > /proc/sysrq-trigger"
>
> I was wondering more about good tests of nfsd's performance on numa;
> that might be more of a question for Greg.
>
To really show a big difference you need a much bigger box, or slower
NUMA interconnects than today's. You also want network cards locally
attached to each node and a metadata heavy (i.e. high rpc call rate)
load.
Greg.--
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