diff mbox series

[net-next,v3,6/8] virtio-net: xsk zero copy xmit kick by threshold

Message ID 20210331071139.15473-7-xuanzhuo@linux.alibaba.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series virtio-net support xdp socket zero copy xmit | expand

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netdev/cc_maintainers success CCed 15 of 15 maintainers
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param fail Was 0 now: 1
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 0 this patch: 0
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netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 55 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
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Commit Message

Xuan Zhuo March 31, 2021, 7:11 a.m. UTC 
After testing, the performance of calling kick every time is not stable.
And if all the packets are sent and kicked again, the performance is not
good. So add a module parameter to specify how many packets are sent to
call a kick.

8 is a relatively stable value with the best performance.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

Comments

Jason Wang April 6, 2021, 6:59 a.m. UTC | #1 
在 2021/3/31 下午3:11, Xuan Zhuo 写道:
> After testing, the performance of calling kick every time is not stable.
> And if all the packets are sent and kicked again, the performance is not
> good. So add a module parameter to specify how many packets are sent to
> call a kick.
>
> 8 is a relatively stable value with the best performance.


Please add some perf numbers here.

Thanks


>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
> ---
>   drivers/net/virtio_net.c | 23 ++++++++++++++++++++---
>   1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 259fafcf6028..d7e95f55478d 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -29,10 +29,12 @@ module_param(napi_weight, int, 0444);
>   
>   static bool csum = true, gso = true, napi_tx = true;
>   static int xsk_budget = 32;
> +static int xsk_kick_thr = 8;
>   module_param(csum, bool, 0444);
>   module_param(gso, bool, 0444);
>   module_param(napi_tx, bool, 0644);
>   module_param(xsk_budget, int, 0644);
> +module_param(xsk_kick_thr, int, 0644);
>   
>   /* FIXME: MTU in config. */
>   #define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
> @@ -2612,6 +2614,8 @@ static int virtnet_xsk_xmit_batch(struct send_queue *sq,
>   	struct xdp_desc desc;
>   	int err, packet = 0;
>   	int ret = -EAGAIN;
> +	int need_kick = 0;
> +	int kicks = 0;
>   
>   	if (sq->xsk.last_desc.addr) {
>   		err = virtnet_xsk_xmit(sq, pool, &sq->xsk.last_desc);
> @@ -2619,6 +2623,7 @@ static int virtnet_xsk_xmit_batch(struct send_queue *sq,
>   			return -EBUSY;
>   
>   		++packet;
> +		++need_kick;
>   		--budget;
>   		sq->xsk.last_desc.addr = 0;
>   	}
> @@ -2642,13 +2647,25 @@ static int virtnet_xsk_xmit_batch(struct send_queue *sq,
>   		}
>   
>   		++packet;
> +		++need_kick;
> +		if (need_kick > xsk_kick_thr) {
> +			if (virtqueue_kick_prepare(sq->vq) &&
> +			    virtqueue_notify(sq->vq))
> +				++kicks;
> +
> +			need_kick = 0;
> +		}
>   	}
>   
>   	if (packet) {
> -		if (virtqueue_kick_prepare(sq->vq) &&
> -		    virtqueue_notify(sq->vq)) {
> +		if (need_kick) {
> +			if (virtqueue_kick_prepare(sq->vq) &&
> +			    virtqueue_notify(sq->vq))
> +				++kicks;
> +		}
> +		if (kicks) {
>   			u64_stats_update_begin(&sq->stats.syncp);
> -			sq->stats.kicks += 1;
> +			sq->stats.kicks += kicks;
>   			u64_stats_update_end(&sq->stats.syncp);
>   		}
>
diff mbox series

Patch

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 259fafcf6028..d7e95f55478d 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -29,10 +29,12 @@  module_param(napi_weight, int, 0444);
 
 static bool csum = true, gso = true, napi_tx = true;
 static int xsk_budget = 32;
+static int xsk_kick_thr = 8;
 module_param(csum, bool, 0444);
 module_param(gso, bool, 0444);
 module_param(napi_tx, bool, 0644);
 module_param(xsk_budget, int, 0644);
+module_param(xsk_kick_thr, int, 0644);
 
 /* FIXME: MTU in config. */
 #define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
@@ -2612,6 +2614,8 @@  static int virtnet_xsk_xmit_batch(struct send_queue *sq,
 	struct xdp_desc desc;
 	int err, packet = 0;
 	int ret = -EAGAIN;
+	int need_kick = 0;
+	int kicks = 0;
 
 	if (sq->xsk.last_desc.addr) {
 		err = virtnet_xsk_xmit(sq, pool, &sq->xsk.last_desc);
@@ -2619,6 +2623,7 @@  static int virtnet_xsk_xmit_batch(struct send_queue *sq,
 			return -EBUSY;
 
 		++packet;
+		++need_kick;
 		--budget;
 		sq->xsk.last_desc.addr = 0;
 	}
@@ -2642,13 +2647,25 @@  static int virtnet_xsk_xmit_batch(struct send_queue *sq,
 		}
 
 		++packet;
+		++need_kick;
+		if (need_kick > xsk_kick_thr) {
+			if (virtqueue_kick_prepare(sq->vq) &&
+			    virtqueue_notify(sq->vq))
+				++kicks;
+
+			need_kick = 0;
+		}
 	}
 
 	if (packet) {
-		if (virtqueue_kick_prepare(sq->vq) &&
-		    virtqueue_notify(sq->vq)) {
+		if (need_kick) {
+			if (virtqueue_kick_prepare(sq->vq) &&
+			    virtqueue_notify(sq->vq))
+				++kicks;
+		}
+		if (kicks) {
 			u64_stats_update_begin(&sq->stats.syncp);
-			sq->stats.kicks += 1;
+			sq->stats.kicks += kicks;
 			u64_stats_update_end(&sq->stats.syncp);
 		}