On Mon, Jul 03, 2023 at 09:14:59PM +0200, Peter-Jan Gootzen wrote: > When the Virtio queue is full, a work item is scheduled > to execute in 1ms that retries adding the request to the queue. > This is a large amount of time on the scale on which a > virtio-fs device can operate. When using a DPU this is around > 40us baseline without going to a remote server (4k, QD=1). > This patch queues requests when the Virtio queue is full, > and when a completed request is taken off, immediately fills > it back up with queued requests. > > This reduces the 99.9th percentile latencies in our tests by > 60x and slightly increases the overall throughput, when using a > queue depth 2x the size of the Virtio queue size, with a > DPU-powered virtio-fs device. > > Signed-off-by: Peter-Jan Gootzen <peter-jan@xxxxxxxxxxx> > --- > V4: Removed return value on error changes to simplify patch, > that should be changed in another patch. > V3: Fixed requests falling into the void when -ENOMEM and no new > incoming requests. Virtio-fs now always lets -ENOMEM bubble up to > userspace. Also made queue full condition more explicit with > -ENOSPC in `send_forget_request`. > V2: Not scheduling dispatch work anymore when not needed > and changed delayed_work structs to work_struct structs > > fs/fuse/virtio_fs.c | 32 +++++++++++++++++--------------- > 1 file changed, 17 insertions(+), 15 deletions(-) Reviewed-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
Attachment:
signature.asc
Description: PGP signature
_______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
