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Re: [Qemu-devel] [RFC PATCH] vring: calculate descriptor address directl
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From: |
Peter Lieven |
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Subject: |
Re: [Qemu-devel] [RFC PATCH] vring: calculate descriptor address directly |
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Date: |
Fri, 28 Nov 2014 09:09:42 +0100 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 |
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 <address@hidden>
> 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