| Message ID | 20230123035511.1122358-1-parav@nvidia.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | d0671115869d19ec76d658c4bf86d3211a8ea121 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] virtio-net: Reduce debug name field size to 16 bytes | expand |
On Mon, Jan 23, 2023 at 9:25 AM Parav Pandit <parav@nvidia.com> wrote: > > virtio queue index can be maximum of 65535. 16 bytes are enough to store > the vq name with the existing string prefix. > > With this change, send queue struct saves 24 bytes and receive > queue saves whole cache line worth 64 bytes per structure > due to saving in alignment bytes. > > Pahole results before: > > pahole -s drivers/net/virtio_net.o | \ > grep -e "send_queue" -e "receive_queue" > send_queue 1112 0 > receive_queue 1280 1 > > Pahole results after: > pahole -s drivers/net/virtio_net.o | \ > grep -e "send_queue" -e "receive_queue" > send_queue 1088 0 > receive_queue 1216 1 > > Signed-off-by: Parav Pandit <parav@nvidia.com> > --- > drivers/net/virtio_net.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index a170b0075dcf..3855b8524300 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -134,7 +134,7 @@ struct send_queue { > struct scatterlist sg[MAX_SKB_FRAGS + 2]; > > /* Name of the send queue: output.$index */ > - char name[40]; > + char name[16]; > > struct virtnet_sq_stats stats; > > @@ -171,7 +171,7 @@ struct receive_queue { > unsigned int min_buf_len; > > /* Name of this receive queue: input.$index */ > - char name[40]; > + char name[16]; > > struct xdp_rxq_info xdp_rxq; > }; > -- > 2.26.2 > Looks good to me. Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Hello: This patch was applied to netdev/net-next.git (master) by David S. Miller <davem@davemloft.net>: On Mon, 23 Jan 2023 05:55:11 +0200 you wrote: > virtio queue index can be maximum of 65535. 16 bytes are enough to store > the vq name with the existing string prefix. > > With this change, send queue struct saves 24 bytes and receive > queue saves whole cache line worth 64 bytes per structure > due to saving in alignment bytes. > > [...] Here is the summary with links: - [net-next] virtio-net: Reduce debug name field size to 16 bytes https://git.kernel.org/netdev/net-next/c/d0671115869d You are awesome, thank you!
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index a170b0075dcf..3855b8524300 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -134,7 +134,7 @@ struct send_queue { struct scatterlist sg[MAX_SKB_FRAGS + 2]; /* Name of the send queue: output.$index */ - char name[40]; + char name[16]; struct virtnet_sq_stats stats; @@ -171,7 +171,7 @@ struct receive_queue { unsigned int min_buf_len; /* Name of this receive queue: input.$index */ - char name[40]; + char name[16]; struct xdp_rxq_info xdp_rxq; };
virtio queue index can be maximum of 65535. 16 bytes are enough to store the vq name with the existing string prefix. With this change, send queue struct saves 24 bytes and receive queue saves whole cache line worth 64 bytes per structure due to saving in alignment bytes. Pahole results before: pahole -s drivers/net/virtio_net.o | \ grep -e "send_queue" -e "receive_queue" send_queue 1112 0 receive_queue 1280 1 Pahole results after: pahole -s drivers/net/virtio_net.o | \ grep -e "send_queue" -e "receive_queue" send_queue 1088 0 receive_queue 1216 1 Signed-off-by: Parav Pandit <parav@nvidia.com> --- drivers/net/virtio_net.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)