From: Peter Lieven <pl@kamp.de>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org
Cc: kwolf@redhat.com, famz@redhat.com, benoit@irqsave.net,
ming.lei@canonical.com, armbru@redhat.com, mreitz@redhat.com,
stefanha@redhat.com
Subject: Re: [Qemu-devel] [RFC PATCH] vring: calculate descriptor address directly
Date: Fri, 28 Nov 2014 09:09:42 +0100 [thread overview]
Message-ID: <54782DC6.4010704@kamp.de> (raw)
In-Reply-To: <547755FE.10707@redhat.com>
Am 27.11.2014 um 17:49 schrieb Paolo Bonzini:
>
> On 27/11/2014 11:15, Peter Lieven wrote:
>> vring_map causes a huge overhead by calling memory_region_find everytime.
>> the vring_map is executed already on vring_setup and there is also the memory
>> region referenced.
>>
>> Signed-off-by: Peter Lieven <pl@kamp.de>
> vring_map/unmap is going to disappear and be replaced by
> address_space_map/unmap, so for now I'd rather keep it...
the issue with vring_map/unmap is that it is called at every vring_pop/push to calculate
the descriptor ptr. its ok to call it in vring_setup/destroy and there it doesn't hurt.
looking at address_space_map/unmap this would be expensive as well if it is called
in every vring_pop/push.
Peter
prev parent reply other threads:[~2014-11-28 8:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-27 10:15 [Qemu-devel] [RFC PATCH] vring: calculate descriptor address directly Peter Lieven
2014-11-27 16:49 ` Paolo Bonzini
2014-11-28 8:09 ` Peter Lieven [this message]
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