Re: [Qemu-devel] [PATCH 2/2] virtio-scsi: Optimize virtio_scsi_init_req

2014-09-11 Thread Paolo Bonzini
Similar nits to patch 1, but a good patch nevertheless! Il 11/09/2014 12:16, Fam Zheng ha scritto: > The VirtQueueElement is a very big structure (> 4k), since it will be > initialzed by virtqueue_pop, we can save the expensive zeroing here. > > This saves a few nanoseconds per request in my test

[Qemu-devel] [PATCH 2/2] virtio-scsi: Optimize virtio_scsi_init_req

2014-09-11 Thread Fam Zheng
The VirtQueueElement is a very big structure (> 4k), since it will be initialzed by virtqueue_pop, we can save the expensive zeroing here. This saves a few nanoseconds per request in my test: [fio-test] rw bs iodepthjobs bw iops latency --