similar to: [PATCH net-next RFC] virtio-net: drop rq->max and rq->num

It looks like there's no need for those two fields: - Unless there's a failure for the first refill try, rq->max should be always equal to the vring size. - rq->num is only used to determine the condition that we need to do the refill, we could check vq->num_free instead. - rq->num was required to be increased or decreased explicitly after each get/put which results a

It looks like there's no need for those two fields: - Unless there's a failure for the first refill try, rq->max should be always equal to the vring size. - rq->num is only used to determine the condition that we need to do the refill, we could check vq->num_free instead. - rq->num was required to be increased or decreased explicitly after each get/put which results a

Rusty Russell <rusty at rustcorp.com.au> writes: > Jason Wang <jasowang at redhat.com> writes: >> It looks like there's no need for those two fields: >> >> - Unless there's a failure for the first refill try, rq->max should be always >> equal to the vring size. >> - rq->num is only used to determine the condition that we need to do the

Rusty Russell <rusty at rustcorp.com.au> writes: > Jason Wang <jasowang at redhat.com> writes: >> It looks like there's no need for those two fields: >> >> - Unless there's a failure for the first refill try, rq->max should be always >> equal to the vring size. >> - rq->num is only used to determine the condition that we need to do the

Jason Wang <jasowang at redhat.com> writes: > It looks like there's no need for those two fields: > > - Unless there's a failure for the first refill try, rq->max should be always > equal to the vring size. > - rq->num is only used to determine the condition that we need to do the refill, > we could check vq->num_free instead. > - rq->num was

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

On 01/07/2014 01:25 PM, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all > workloads. For workloads

On 01/07/2014 01:25 PM, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all > workloads. For workloads

On Wed, Nov 20, 2013 at 07:08:50AM -0500, Jason Wang wrote: > > > ----- ???? ----- > > On Wed, Nov 20, 2013 at 05:07:26PM +0800, Jason Wang wrote: > > > We need decrease the rq->num after we can get a buf through > > > virtqueue_get_buf() even if we could not allocate frag skb. Otherwise, the > > > refill routine won't be triggered under heavy

On Wed, Nov 20, 2013 at 07:08:50AM -0500, Jason Wang wrote: > > > ----- ???? ----- > > On Wed, Nov 20, 2013 at 05:07:26PM +0800, Jason Wang wrote: > > > We need decrease the rq->num after we can get a buf through > > > virtqueue_get_buf() even if we could not allocate frag skb. Otherwise, the > > > refill routine won't be triggered under heavy

On Wed, Nov 20, 2013 at 05:07:26PM +0800, Jason Wang wrote: > We need decrease the rq->num after we can get a buf through > virtqueue_get_buf() even if we could not allocate frag skb. Otherwise, the > refill routine won't be triggered under heavy memory stress since the driver may > still think there's enough room. > > This bug was introduced by commit

On Wed, Nov 20, 2013 at 05:07:26PM +0800, Jason Wang wrote: > We need decrease the rq->num after we can get a buf through > virtqueue_get_buf() even if we could not allocate frag skb. Otherwise, the > refill routine won't be triggered under heavy memory stress since the driver may > still think there's enough room. > > This bug was introduced by commit

The virtio_net driver's mergeable receive buffer allocator uses 4KB packet buffers. For MTU-sized traffic, SKB truesize is > 4KB but only ~1500 bytes of the buffer is used to store packet data, reducing the effective TCP window size substantially. This patch addresses the performance concerns with mergeable receive buffers by allocating MTU-sized packet buffers using page frag allocators.

The virtio_net driver's mergeable receive buffer allocator uses 4KB packet buffers. For MTU-sized traffic, SKB truesize is > 4KB but only ~1500 bytes of the buffer is used to store packet data, reducing the effective TCP window size substantially. This patch addresses the performance concerns with mergeable receive buffers by allocating MTU-sized packet buffers using page frag allocators.

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

On 11/13/2013 06:21 AM, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all workloads. > For workloads