From: Sasha Levin <sasha.levin@oracle.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: rusty@rustcorp.com.au, penberg@kernel.org, will.deacon@arm.com,
marc.zyngier@arm.com, kvm@vger.kernel.org, asias@redhat.com,
jasowang@redhat.com
Subject: Re: [PATCH] virtio-net: fill only rx queues which are being used
Date: Tue, 23 Apr 2013 10:52:43 -0400 [thread overview]
Message-ID: <5176A03B.3080407@oracle.com> (raw)
In-Reply-To: <20130423070845.GA23530@redhat.com>
On 04/23/2013 03:08 AM, Michael S. Tsirkin wrote:
> On Mon, Apr 22, 2013 at 08:35:36PM -0400, Sasha Levin wrote:
>> Due to MQ support we may allocate a whole bunch of rx queues but
>> never use them. With this patch we'll safe the space used by
>> the receive buffers until they are actually in use:
>>
>> sh-4.2# free -h
>> total used free shared buffers cached
>> Mem: 490M 35M 455M 0B 0B 4.1M
>> -/+ buffers/cache: 31M 459M
>> Swap: 0B 0B 0B
>> sh-4.2# ethtool -L eth0 combined 8
>> sh-4.2# free -h
>> total used free shared buffers cached
>> Mem: 490M 162M 327M 0B 0B 4.1M
>> -/+ buffers/cache: 158M 331M
>> Swap: 0B 0B 0B
>>
>> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
>
> Overall the idea looks fine to me.
>
> I also ask myself whether we should enable multiqueue capability
> with big buffers. 130M extra memory seems excessive.
> Want to try on the kvmtools version that has mergeable buffers?
> Memory use should be much lower.
It is indeed, with mergable buffers:
sh-4.2# free -h
total used free shared buffers cached
Mem: 490M 18M 471M 0B 0B 4.1M
-/+ buffers/cache: 14M 476M
Swap: 0B 0B 0B
sh-4.2# ethtool -L eth0 combined 8
sh-4.2# free -h
total used free shared buffers cached
Mem: 490M 26M 464M 0B 0B 4.1M
-/+ buffers/cache: 22M 468M
Swap: 0B 0B 0B
(18MB? Nice! :) )
Thanks,
Sasha
prev parent reply other threads:[~2013-04-23 14:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-23 0:35 [PATCH] virtio-net: fill only rx queues which are being used Sasha Levin
2013-04-23 4:13 ` Rusty Russell
2013-04-23 4:49 ` Sasha Levin
2013-04-23 9:18 ` Will Deacon
2013-04-23 7:08 ` Michael S. Tsirkin
2013-04-23 14:52 ` Sasha Levin [this message]
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