Message ID | 1431317294-16442-1-git-send-email-kys@microsoft.com |
---|---|
State | Changes Requested, archived |
Delegated to: | David Miller |
Headers | show |
On Sun, 2015-05-10 at 21:08 -0700, K. Y. Srinivasan wrote: > Based on the information given to this driver (via the xmit_more skb flag), > we can defer signaling the host if more packets are on the way. This will help > make the host more efficient since it can potentially process a larger batch of > packets. Implement this optimization. trivia: I think that indirecting VMBUS_DATA_PACKET_FLAG_COMPLETTION_REQUESTED into a non-const temporary isn't very useful. Whenever overly long identifiers like VMBUS_<FOO> is used, I think that it'd be better to use it directly and ignore 80 column warnings. Same with the "sizeof(struct nvsp_message)" on two lines. > diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c [] > @@ -743,6 +743,8 @@ static inline int netvsc_send_pkt( > u64 req_id; > int ret; > struct hv_page_buffer *pgbuf; > + u32 vmbus_flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; > + u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound); [] > @@ -769,30 +771,41 @@ static inline int netvsc_send_pkt( [] > + ret = vmbus_sendpacket_pagebuffer_ctl(out_channel, > + pgbuf, > + packet->page_buf_cnt, > + &nvmsg, > + sizeof(struct > + nvsp_message), > + req_id, > + vmbus_flags, > + !packet->xmit_more); [] > netif_tx_stop_queue(netdev_get_tx_queue( > ndev, q_idx)); This could be on one line too. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> -----Original Message----- > From: Joe Perches [mailto:joe@perches.com] > Sent: Sunday, May 10, 2015 10:58 PM > To: KY Srinivasan > Cc: davem@davemloft.net; netdev@vger.kernel.org; linux- > kernel@vger.kernel.org; devel@linuxdriverproject.org; olaf@aepfle.de; > apw@canonical.com; jasowang@redhat.com > Subject: Re: [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to > optimize signaling the host > > On Sun, 2015-05-10 at 21:08 -0700, K. Y. Srinivasan wrote: > > Based on the information given to this driver (via the xmit_more skb flag), > > we can defer signaling the host if more packets are on the way. This will > help > > make the host more efficient since it can potentially process a larger batch > of > > packets. Implement this optimization. > > trivia: > > I think that indirecting > VMBUS_DATA_PACKET_FLAG_COMPLETTION_REQUESTED > into a non-const temporary isn't very useful. > > Whenever overly long identifiers like VMBUS_<FOO> is used, > I think that it'd be better to use it directly and ignore > 80 column warnings. Thanks Joe; if Dave agrees, I can send v6 of this patch out. Regards, K. Y > > Same with the "sizeof(struct nvsp_message)" on two lines. > > > diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c > [] > > @@ -743,6 +743,8 @@ static inline int netvsc_send_pkt( > > u64 req_id; > > int ret; > > struct hv_page_buffer *pgbuf; > > + u32 vmbus_flags = > VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; > > + u32 ring_avail = hv_ringbuf_avail_percent(&out_channel- > >outbound); > [] > > @@ -769,30 +771,41 @@ static inline int netvsc_send_pkt( > [] > > + ret = vmbus_sendpacket_pagebuffer_ctl(out_channel, > > + pgbuf, > > + packet->page_buf_cnt, > > + &nvmsg, > > + sizeof(struct > > + nvsp_message), > > + req_id, > > + vmbus_flags, > > + !packet->xmit_more); > > [] > > > netif_tx_stop_queue(netdev_get_tx_queue( > > ndev, q_idx)); > > This could be on one line too. > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: KY Srinivasan <kys@microsoft.com> Date: Mon, 11 May 2015 08:59:53 +0000 > > >> -----Original Message----- >> From: Joe Perches [mailto:joe@perches.com] >> Sent: Sunday, May 10, 2015 10:58 PM >> To: KY Srinivasan >> Cc: davem@davemloft.net; netdev@vger.kernel.org; linux- >> kernel@vger.kernel.org; devel@linuxdriverproject.org; olaf@aepfle.de; >> apw@canonical.com; jasowang@redhat.com >> Subject: Re: [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to >> optimize signaling the host >> >> On Sun, 2015-05-10 at 21:08 -0700, K. Y. Srinivasan wrote: >> > Based on the information given to this driver (via the xmit_more skb flag), >> > we can defer signaling the host if more packets are on the way. This will >> help >> > make the host more efficient since it can potentially process a larger batch >> of >> > packets. Implement this optimization. >> >> trivia: >> >> I think that indirecting >> VMBUS_DATA_PACKET_FLAG_COMPLETTION_REQUESTED >> into a non-const temporary isn't very useful. >> >> Whenever overly long identifiers like VMBUS_<FOO> is used, >> I think that it'd be better to use it directly and ignore >> 80 column warnings. > > Thanks Joe; if Dave agrees, I can send v6 of this patch out. Sure, respin a v6. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index ea091bc..7fdf3e8 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -743,6 +743,8 @@ static inline int netvsc_send_pkt( u64 req_id; int ret; struct hv_page_buffer *pgbuf; + u32 vmbus_flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; + u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound); nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT; if (packet->is_data_pkt) { @@ -769,30 +771,41 @@ static inline int netvsc_send_pkt( if (out_channel->rescind) return -ENODEV; + /* + * It is possible that once we successfully place this packet + * on the ringbuffer, we may stop the queue. In that case, we want + * to notify the host independent of the xmit_more flag. We don't + * need to be precise here; in the worst case we may signal the host + * unnecessarily. + */ + if (ring_avail < (RING_AVAIL_PERCENT_LOWATER + 1)) + packet->xmit_more = false; + if (packet->page_buf_cnt) { pgbuf = packet->cp_partial ? packet->page_buf + packet->rmsg_pgcnt : packet->page_buf; - ret = vmbus_sendpacket_pagebuffer(out_channel, - pgbuf, - packet->page_buf_cnt, - &nvmsg, - sizeof(struct nvsp_message), - req_id); + ret = vmbus_sendpacket_pagebuffer_ctl(out_channel, + pgbuf, + packet->page_buf_cnt, + &nvmsg, + sizeof(struct + nvsp_message), + req_id, + vmbus_flags, + !packet->xmit_more); } else { - ret = vmbus_sendpacket( - out_channel, &nvmsg, - sizeof(struct nvsp_message), - req_id, - VM_PKT_DATA_INBAND, - VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); + ret = vmbus_sendpacket_ctl(out_channel, &nvmsg, + sizeof(struct nvsp_message), + req_id, + VM_PKT_DATA_INBAND, + vmbus_flags, !packet->xmit_more); } if (ret == 0) { atomic_inc(&net_device->num_outstanding_sends); atomic_inc(&net_device->queue_sends[q_idx]); - if (hv_ringbuf_avail_percent(&out_channel->outbound) < - RING_AVAIL_PERCENT_LOWATER) { + if (ring_avail < RING_AVAIL_PERCENT_LOWATER) { netif_tx_stop_queue(netdev_get_tx_queue( ndev, q_idx));
Based on the information given to this driver (via the xmit_more skb flag), we can defer signaling the host if more packets are on the way. This will help make the host more efficient since it can potentially process a larger batch of packets. Implement this optimization. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> --- v2: Fixed up indentation based on feedback from David Miller. v3,v4: If the queue could be stopped, deal with that condition: Eric Dumazet <eric.dumazet@gmail.com> v5: Fixed up indentation based on feedback from David Miller. drivers/net/hyperv/netvsc.c | 41 +++++++++++++++++++++++++++-------------- 1 files changed, 27 insertions(+), 14 deletions(-)