| Message ID | 1412124801-32096-1-git-send-email-ast@plumgrid.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Tue, 2014-09-30 at 17:53 -0700, Alexei Starovoitov wrote: > This patch demonstrates the effect of delaying update of HW tailptr. > (based on earlier patch by Jesper) > > burst=1 is the default. It sends one packet with xmit_more=false > burst=2 sends one packet with xmit_more=true and > 2nd copy of the same packet with xmit_more=false > burst=3 sends two copies of the same packet with xmit_more=true and > 3rd copy with xmit_more=false > > Performance with ixgbe (usec 30): > burst=1 tx:9.2 Mpps > burst=2 tx:13.5 Mpps > burst=3 tx:14.5 Mpps full 10G line rate > > Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> > --- Very good, thanks Alexei Signed-off-by: Eric Dumazet <edumazet@google.com> -- 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
On Tue, 30 Sep 2014 17:53:21 -0700 Alexei Starovoitov <ast@plumgrid.com> wrote: > This patch demonstrates the effect of delaying update of HW tailptr. > (based on earlier patch by Jesper) > > burst=1 is the default. It sends one packet with xmit_more=false > burst=2 sends one packet with xmit_more=true and > 2nd copy of the same packet with xmit_more=false > burst=3 sends two copies of the same packet with xmit_more=true and > 3rd copy with xmit_more=false > > Performance with ixgbe (usec 30): > burst=1 tx:9.2 Mpps > burst=2 tx:13.5 Mpps > burst=3 tx:14.5 Mpps full 10G line rate > > Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> > --- Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Thanks Alexei
From: Alexei Starovoitov <ast@plumgrid.com> Date: Tue, 30 Sep 2014 17:53:21 -0700 > This patch demonstrates the effect of delaying update of HW tailptr. > (based on earlier patch by Jesper) > > burst=1 is the default. It sends one packet with xmit_more=false > burst=2 sends one packet with xmit_more=true and > 2nd copy of the same packet with xmit_more=false > burst=3 sends two copies of the same packet with xmit_more=true and > 3rd copy with xmit_more=false > > Performance with ixgbe (usec 30): > burst=1 tx:9.2 Mpps > burst=2 tx:13.5 Mpps > burst=3 tx:14.5 Mpps full 10G line rate > > Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Applied, great work. -- 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
On Wed, 01 Oct 2014 22:08:39 -0400 (EDT) David Miller <davem@davemloft.net> wrote: > From: Alexei Starovoitov <ast@plumgrid.com> > Date: Tue, 30 Sep 2014 17:53:21 -0700 > > > This patch demonstrates the effect of delaying update of HW tailptr. > > (based on earlier patch by Jesper) > > > > burst=1 is the default. It sends one packet with xmit_more=false > > burst=2 sends one packet with xmit_more=true and > > 2nd copy of the same packet with xmit_more=false > > burst=3 sends two copies of the same packet with xmit_more=true and > > 3rd copy with xmit_more=false > > > > Performance with ixgbe (usec 30): > > burst=1 tx:9.2 Mpps > > burst=2 tx:13.5 Mpps > > burst=3 tx:14.5 Mpps full 10G line rate > > > > Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> > > Applied, great work. Updated my pktgen script "pktgen02_burst.sh" for supporting this new "burst" option: https://github.com/netoptimizer/network-testing/commit/cb625712f8efb https://github.com/netoptimizer/network-testing/blob/master/pktgen/pktgen02_burst.sh
diff --git a/Documentation/networking/pktgen.txt b/Documentation/networking/pktgen.txt index 0dffc6e37902..6915c6b27869 100644 --- a/Documentation/networking/pktgen.txt +++ b/Documentation/networking/pktgen.txt @@ -99,6 +99,9 @@ Examples: pgset "clone_skb 1" sets the number of copies of the same packet pgset "clone_skb 0" use single SKB for all transmits + pgset "burst 8" uses xmit_more API to queue 8 copies of the same + packet and update HW tx queue tail pointer once. + "burst 1" is the default pgset "pkt_size 9014" sets packet size to 9014 pgset "frags 5" packet will consist of 5 fragments pgset "count 200000" sets number of packets to send, set to zero diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 5c728aaf8d6c..443256bdcddc 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -387,6 +387,7 @@ struct pktgen_dev { u16 queue_map_min; u16 queue_map_max; __u32 skb_priority; /* skb priority field */ + unsigned int burst; /* number of duplicated packets to burst */ int node; /* Memory node */ #ifdef CONFIG_XFRM @@ -613,6 +614,9 @@ static int pktgen_if_show(struct seq_file *seq, void *v) if (pkt_dev->traffic_class) seq_printf(seq, " traffic_class: 0x%02x\n", pkt_dev->traffic_class); + if (pkt_dev->burst > 1) + seq_printf(seq, " burst: %d\n", pkt_dev->burst); + if (pkt_dev->node >= 0) seq_printf(seq, " node: %d\n", pkt_dev->node); @@ -1124,6 +1128,16 @@ static ssize_t pktgen_if_write(struct file *file, pkt_dev->dst_mac_count); return count; } + if (!strcmp(name, "burst")) { + len = num_arg(&user_buffer[i], 10, &value); + if (len < 0) + return len; + + i += len; + pkt_dev->burst = value < 1 ? 1 : value; + sprintf(pg_result, "OK: burst=%d", pkt_dev->burst); + return count; + } if (!strcmp(name, "node")) { len = num_arg(&user_buffer[i], 10, &value); if (len < 0) @@ -3297,6 +3311,7 @@ static void pktgen_wait_for_skb(struct pktgen_dev *pkt_dev) static void pktgen_xmit(struct pktgen_dev *pkt_dev) { + unsigned int burst = ACCESS_ONCE(pkt_dev->burst); struct net_device *odev = pkt_dev->odev; struct netdev_queue *txq; int ret; @@ -3347,8 +3362,10 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) pkt_dev->last_ok = 0; goto unlock; } - atomic_inc(&(pkt_dev->skb->users)); - ret = netdev_start_xmit(pkt_dev->skb, odev, txq, false); + atomic_add(burst, &pkt_dev->skb->users); + +xmit_more: + ret = netdev_start_xmit(pkt_dev->skb, odev, txq, --burst > 0); switch (ret) { case NETDEV_TX_OK: @@ -3356,6 +3373,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) pkt_dev->sofar++; pkt_dev->seq_num++; pkt_dev->tx_bytes += pkt_dev->last_pkt_size; + if (burst > 0 && !netif_xmit_frozen_or_drv_stopped(txq)) + goto xmit_more; break; case NET_XMIT_DROP: case NET_XMIT_CN: @@ -3374,6 +3393,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) atomic_dec(&(pkt_dev->skb->users)); pkt_dev->last_ok = 0; } + if (unlikely(burst)) + atomic_sub(burst, &pkt_dev->skb->users); unlock: HARD_TX_UNLOCK(odev, txq); @@ -3572,6 +3593,7 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname) pkt_dev->svlan_p = 0; pkt_dev->svlan_cfi = 0; pkt_dev->svlan_id = 0xffff; + pkt_dev->burst = 1; pkt_dev->node = -1; err = pktgen_setup_dev(t->net, pkt_dev, ifname);
This patch demonstrates the effect of delaying update of HW tailptr. (based on earlier patch by Jesper) burst=1 is the default. It sends one packet with xmit_more=false burst=2 sends one packet with xmit_more=true and 2nd copy of the same packet with xmit_more=false burst=3 sends two copies of the same packet with xmit_more=true and 3rd copy with xmit_more=false Performance with ixgbe (usec 30): burst=1 tx:9.2 Mpps burst=2 tx:13.5 Mpps burst=3 tx:14.5 Mpps full 10G line rate Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> --- v1 -> v2: - simplified burst counting logic (suggested by Eric) - re-tested on ixgbe, mlx4, bnx2x RFC -> v1: - added netif_xmit_frozen_or_drv_stopped() check, since bnx2x stops the queue and returns TX_OK (suggested by Eric) - read pkt_dev->burst once to avoid races (suggested by Eric) - changed 'int burst' to 'unsigned int burst' - updated doc - tested on ixgbe, mlx4, bnx2x Comparing to Jesper patch this one amortizes the cost of spin_lock and atomic_inc by doing HARD_TX_LOCK and atomic_add(N) once across N packets. Documentation/networking/pktgen.txt | 3 +++ net/core/pktgen.c | 26 ++++++++++++++++++++++++-- 2 files changed, 27 insertions(+), 2 deletions(-)