| Message ID | 20191217150737.24039-1-ktraynor@redhat.com |
|---|---|
| State | Accepted |
| Delegated to: | Ilya Maximets |
| Headers | show |
| Series | [ovs-dev] netdev-dpdk: Fix sw stats perf drop. | expand |
On 17 Dec 2019, at 16:07, Kevin Traynor wrote: > Accessing the sw stats in the vhost datapath of a PVP test > can incur a performance drop of ~2%. > > Most of the time these stats will just be getting zero added > to them. By checking if there is a non-zero update first, we > can avoid accessing them when they won't be updated and avoid > the performance drop. > > Fixes: 2f862c712e52 ("netdev-dpdk: Detailed packet drop statistics.") > Signed-off-by: Kevin Traynor <ktraynor@redhat.com> > --- LGTM, Acked-by: Eelco Chaudron <echaudro@redhat.com>
On 17.12.2019 16:07, Kevin Traynor wrote: > Accessing the sw stats in the vhost datapath of a PVP test > can incur a performance drop of ~2%. > > Most of the time these stats will just be getting zero added > to them. By checking if there is a non-zero update first, we > can avoid accessing them when they won't be updated and avoid > the performance drop. > > Fixes: 2f862c712e52 ("netdev-dpdk: Detailed packet drop statistics.") > Signed-off-by: Kevin Traynor <ktraynor@redhat.com> > --- We actually have similar checks for physical ports, so it's sane to have them for vhost too. Thanks Kevin and Eelco! Applied to master. Best regards, Ilya Maximets.
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c index 89c73a29b..238f29a2a 100644 --- a/lib/netdev-dpdk.c +++ b/lib/netdev-dpdk.c @@ -2175,5 +2175,4 @@ netdev_dpdk_vhost_update_rx_counters(struct netdev_dpdk *dev, int qos_drops) { - struct netdev_dpdk_sw_stats *sw_stats = dev->sw_stats; struct netdev_stats *stats = &dev->stats; struct dp_packet *packet; @@ -2206,5 +2205,7 @@ netdev_dpdk_vhost_update_rx_counters(struct netdev_dpdk *dev, } - sw_stats->rx_qos_drops += qos_drops; + if (OVS_UNLIKELY(qos_drops)) { + dev->sw_stats->rx_qos_drops += qos_drops; + } } @@ -2370,5 +2371,4 @@ netdev_dpdk_vhost_update_tx_counters(struct netdev_dpdk *dev, struct netdev_dpdk_sw_stats *sw_stats_add) { - struct netdev_dpdk_sw_stats *sw_stats = dev->sw_stats; int dropped = sw_stats_add->tx_mtu_exceeded_drops + sw_stats_add->tx_qos_drops + @@ -2385,8 +2385,12 @@ netdev_dpdk_vhost_update_tx_counters(struct netdev_dpdk *dev, } - sw_stats->tx_retries += sw_stats_add->tx_retries; - sw_stats->tx_failure_drops += sw_stats_add->tx_failure_drops; - sw_stats->tx_mtu_exceeded_drops += sw_stats_add->tx_mtu_exceeded_drops; - sw_stats->tx_qos_drops += sw_stats_add->tx_qos_drops; + if (OVS_UNLIKELY(dropped || sw_stats_add->tx_retries)) { + struct netdev_dpdk_sw_stats *sw_stats = dev->sw_stats; + + sw_stats->tx_retries += sw_stats_add->tx_retries; + sw_stats->tx_failure_drops += sw_stats_add->tx_failure_drops; + sw_stats->tx_mtu_exceeded_drops += sw_stats_add->tx_mtu_exceeded_drops; + sw_stats->tx_qos_drops += sw_stats_add->tx_qos_drops; + } }
Accessing the sw stats in the vhost datapath of a PVP test can incur a performance drop of ~2%. Most of the time these stats will just be getting zero added to them. By checking if there is a non-zero update first, we can avoid accessing them when they won't be updated and avoid the performance drop. Fixes: 2f862c712e52 ("netdev-dpdk: Detailed packet drop statistics.") Signed-off-by: Kevin Traynor <ktraynor@redhat.com> --- lib/netdev-dpdk.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-)