Messages in this thread | | | Date | Thu, 6 Oct 2011 15:53:09 +0200 | From | Jens Axboe <> | Subject | Re: [PATCH 5/5] virtio-blk: implement ->make_request |
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On Wed, Oct 05 2011, Christoph Hellwig wrote: > Add an alternate I/O path that implements ->make_request for virtio-blk. > This is required for high IOPs devices which get slowed down to 1/5th of > the native speed by all the locking, memory allocation and other overhead > in the request based I/O path.
We definitely have some performance fruit hanging rather low in that path, but a factor 5 performance difference sounds insanely excessive. I haven't looked at virtio_blk in detail, but I've done 500K+ IOPS on request based drivers before (yes, on real hardware). So it could be that virtio_blk is just doing things rather suboptimally in some places, and that it would be possible to claim most of that speedup there too.
-- Jens Axboe
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