| Message ID | 3edbcfacf7ff4fbe8b527a372ef73d1a6db17144.1684397037.git.matsuda-daisuke@fujitsu.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | On-Demand Paging on SoftRoCE | expand |
On Thu, May 18, 2023 5:22 PM Daisuke Matsuda wrote: > Both responder and completer need to sleep to execute page-fault when used > with ODP. It can happen when they are going to access user MRs, so tasks > must be executed in process context for such cases. > > Additionally, current implementation seldom defers tasks to workqueue, but > instead defers to a softirq context running do_task(). It is called from > rxe_resp_queue_pkt() and rxe_comp_queue_pkt() in SOFTIRQ_NET_RX context and > can last until maximum RXE_MAX_ITERATIONS (=1024) loops are executed. The > problem is the that task execuion appears to be anonymous loads in the > system and that the loop can throttle other softirqs on the same CPU. > > This patch makes responder and completer codes run in process context for > ODP and the problem described above. > > Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com> > --- Some people may be concerned about performance change caused by this patch, so I measured the performance using 2 VMs on the same host. Here are the settings: Host: CPU cores: 32 MEM 64GiB Hypervisor: KVM Guest: vCPUs: 8 Mem: 12 GiB OS: CentOS 9 Stream kernel vers: 6.4.0-rc2 (latest jgg-for-next as of 5/18, 2023) Conditions: Operations: send, write, read I measured the performance of the latest jgg-for-next kernel. After that I applied all ODP patches and measured the performance again. The results are shown below. The performance often fluctuates, so it is difficult to say which one is better. However, it seems there is no regression after the change. ## latest jgg-for-next (Current) [send] --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 258.32 0.004133 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 335.09 0.005361 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 240.24 0.003844 --------------------------------------------------------------------------------------- [write] --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 281.40 0.004502 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 347.02 0.005552 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 280.36 0.004486 --------------------------------------------------------------------------------------- [read] --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 271.30 0.004341 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 266.44 0.004263 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 226.94 0.003631 --------------------------------------------------------------------------------------- ## After applying the ODP patches send --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 289.26 0.004628 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 268.85 0.004302 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 320.81 0.005133 --------------------------------------------------------------------------------------- write --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 288.98 0.004624 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 261.98 0.004192 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 274.59 0.004393 --------------------------------------------------------------------------------------- read --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 324.56 0.005193 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 294.21 0.004707 --------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------- #bytes #iterations BW peak[MB/sec] BW average[MB/sec] MsgRate[Mpps] 65536 200000 0.00 256.60 0.004106 ---------------------------------------------------------------------------------------
On 5/18/23 03:21, Daisuke Matsuda wrote: > Both responder and completer need to sleep to execute page-fault when used > with ODP. It can happen when they are going to access user MRs, so tasks > must be executed in process context for such cases. > > Additionally, current implementation seldom defers tasks to workqueue, but > instead defers to a softirq context running do_task(). It is called from > rxe_resp_queue_pkt() and rxe_comp_queue_pkt() in SOFTIRQ_NET_RX context and > can last until maximum RXE_MAX_ITERATIONS (=1024) loops are executed. The > problem is the that task execuion appears to be anonymous loads in the > system and that the loop can throttle other softirqs on the same CPU. > > This patch makes responder and completer codes run in process context for > ODP and the problem described above. > > Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com> > --- > drivers/infiniband/sw/rxe/rxe_comp.c | 12 +----------- > drivers/infiniband/sw/rxe/rxe_hw_counters.c | 1 - > drivers/infiniband/sw/rxe/rxe_hw_counters.h | 1 - > drivers/infiniband/sw/rxe/rxe_resp.c | 13 +------------ > 4 files changed, 2 insertions(+), 25 deletions(-) > > diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c > index db18ace74d2b..671fdb645030 100644 > --- a/drivers/infiniband/sw/rxe/rxe_comp.c > +++ b/drivers/infiniband/sw/rxe/rxe_comp.c > @@ -128,18 +128,8 @@ void retransmit_timer(struct timer_list *t) > > void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb) > { > - int must_sched; > - > skb_queue_tail(&qp->resp_pkts, skb); > - > - must_sched = skb_queue_len(&qp->resp_pkts) > 1; > - if (must_sched != 0) > - rxe_counter_inc(SKB_TO_PKT(skb)->rxe, RXE_CNT_COMPLETER_SCHED); > - > - if (must_sched) > - rxe_sched_task(&qp->comp.task); > - else > - rxe_run_task(&qp->comp.task); > + rxe_sched_task(&qp->comp.task); > } > > static inline enum comp_state get_wqe(struct rxe_qp *qp, > diff --git a/drivers/infiniband/sw/rxe/rxe_hw_counters.c b/drivers/infiniband/sw/rxe/rxe_hw_counters.c > index a012522b577a..dc23cf3a6967 100644 > --- a/drivers/infiniband/sw/rxe/rxe_hw_counters.c > +++ b/drivers/infiniband/sw/rxe/rxe_hw_counters.c > @@ -14,7 +14,6 @@ static const struct rdma_stat_desc rxe_counter_descs[] = { > [RXE_CNT_RCV_RNR].name = "rcvd_rnr_err", > [RXE_CNT_SND_RNR].name = "send_rnr_err", > [RXE_CNT_RCV_SEQ_ERR].name = "rcvd_seq_err", > - [RXE_CNT_COMPLETER_SCHED].name = "ack_deferred", > [RXE_CNT_RETRY_EXCEEDED].name = "retry_exceeded_err", > [RXE_CNT_RNR_RETRY_EXCEEDED].name = "retry_rnr_exceeded_err", > [RXE_CNT_COMP_RETRY].name = "completer_retry_err", > diff --git a/drivers/infiniband/sw/rxe/rxe_hw_counters.h b/drivers/infiniband/sw/rxe/rxe_hw_counters.h > index 71f4d4fa9dc8..303da0e3134a 100644 > --- a/drivers/infiniband/sw/rxe/rxe_hw_counters.h > +++ b/drivers/infiniband/sw/rxe/rxe_hw_counters.h > @@ -18,7 +18,6 @@ enum rxe_counters { > RXE_CNT_RCV_RNR, > RXE_CNT_SND_RNR, > RXE_CNT_RCV_SEQ_ERR, > - RXE_CNT_COMPLETER_SCHED, > RXE_CNT_RETRY_EXCEEDED, > RXE_CNT_RNR_RETRY_EXCEEDED, > RXE_CNT_COMP_RETRY, > diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c > index 68f6cd188d8e..ba0222bfce9e 100644 > --- a/drivers/infiniband/sw/rxe/rxe_resp.c > +++ b/drivers/infiniband/sw/rxe/rxe_resp.c > @@ -46,21 +46,10 @@ static char *resp_state_name[] = { > [RESPST_EXIT] = "EXIT", > }; > > -/* rxe_recv calls here to add a request packet to the input queue */ > void rxe_resp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb) > { > - int must_sched; > - struct rxe_pkt_info *pkt = SKB_TO_PKT(skb); > - > skb_queue_tail(&qp->req_pkts, skb); > - > - must_sched = (pkt->opcode == IB_OPCODE_RC_RDMA_READ_REQUEST) || > - (skb_queue_len(&qp->req_pkts) > 1); > - > - if (must_sched) > - rxe_sched_task(&qp->resp.task); > - else > - rxe_run_task(&qp->resp.task); > + rxe_sched_task(&qp->resp.task); > } > > static inline enum resp_states get_req(struct rxe_qp *qp, Looks good. Reviewed-by: Bob Pearson <rpearsonhpe@gmail.com>
diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c index db18ace74d2b..671fdb645030 100644 --- a/drivers/infiniband/sw/rxe/rxe_comp.c +++ b/drivers/infiniband/sw/rxe/rxe_comp.c @@ -128,18 +128,8 @@ void retransmit_timer(struct timer_list *t) void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb) { - int must_sched; - skb_queue_tail(&qp->resp_pkts, skb); - - must_sched = skb_queue_len(&qp->resp_pkts) > 1; - if (must_sched != 0) - rxe_counter_inc(SKB_TO_PKT(skb)->rxe, RXE_CNT_COMPLETER_SCHED); - - if (must_sched) - rxe_sched_task(&qp->comp.task); - else - rxe_run_task(&qp->comp.task); + rxe_sched_task(&qp->comp.task); } static inline enum comp_state get_wqe(struct rxe_qp *qp, diff --git a/drivers/infiniband/sw/rxe/rxe_hw_counters.c b/drivers/infiniband/sw/rxe/rxe_hw_counters.c index a012522b577a..dc23cf3a6967 100644 --- a/drivers/infiniband/sw/rxe/rxe_hw_counters.c +++ b/drivers/infiniband/sw/rxe/rxe_hw_counters.c @@ -14,7 +14,6 @@ static const struct rdma_stat_desc rxe_counter_descs[] = { [RXE_CNT_RCV_RNR].name = "rcvd_rnr_err", [RXE_CNT_SND_RNR].name = "send_rnr_err", [RXE_CNT_RCV_SEQ_ERR].name = "rcvd_seq_err", - [RXE_CNT_COMPLETER_SCHED].name = "ack_deferred", [RXE_CNT_RETRY_EXCEEDED].name = "retry_exceeded_err", [RXE_CNT_RNR_RETRY_EXCEEDED].name = "retry_rnr_exceeded_err", [RXE_CNT_COMP_RETRY].name = "completer_retry_err", diff --git a/drivers/infiniband/sw/rxe/rxe_hw_counters.h b/drivers/infiniband/sw/rxe/rxe_hw_counters.h index 71f4d4fa9dc8..303da0e3134a 100644 --- a/drivers/infiniband/sw/rxe/rxe_hw_counters.h +++ b/drivers/infiniband/sw/rxe/rxe_hw_counters.h @@ -18,7 +18,6 @@ enum rxe_counters { RXE_CNT_RCV_RNR, RXE_CNT_SND_RNR, RXE_CNT_RCV_SEQ_ERR, - RXE_CNT_COMPLETER_SCHED, RXE_CNT_RETRY_EXCEEDED, RXE_CNT_RNR_RETRY_EXCEEDED, RXE_CNT_COMP_RETRY, diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c index 68f6cd188d8e..ba0222bfce9e 100644 --- a/drivers/infiniband/sw/rxe/rxe_resp.c +++ b/drivers/infiniband/sw/rxe/rxe_resp.c @@ -46,21 +46,10 @@ static char *resp_state_name[] = { [RESPST_EXIT] = "EXIT", }; -/* rxe_recv calls here to add a request packet to the input queue */ void rxe_resp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb) { - int must_sched; - struct rxe_pkt_info *pkt = SKB_TO_PKT(skb); - skb_queue_tail(&qp->req_pkts, skb); - - must_sched = (pkt->opcode == IB_OPCODE_RC_RDMA_READ_REQUEST) || - (skb_queue_len(&qp->req_pkts) > 1); - - if (must_sched) - rxe_sched_task(&qp->resp.task); - else - rxe_run_task(&qp->resp.task); + rxe_sched_task(&qp->resp.task); } static inline enum resp_states get_req(struct rxe_qp *qp,
Both responder and completer need to sleep to execute page-fault when used with ODP. It can happen when they are going to access user MRs, so tasks must be executed in process context for such cases. Additionally, current implementation seldom defers tasks to workqueue, but instead defers to a softirq context running do_task(). It is called from rxe_resp_queue_pkt() and rxe_comp_queue_pkt() in SOFTIRQ_NET_RX context and can last until maximum RXE_MAX_ITERATIONS (=1024) loops are executed. The problem is the that task execuion appears to be anonymous loads in the system and that the loop can throttle other softirqs on the same CPU. This patch makes responder and completer codes run in process context for ODP and the problem described above. Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com> --- drivers/infiniband/sw/rxe/rxe_comp.c | 12 +----------- drivers/infiniband/sw/rxe/rxe_hw_counters.c | 1 - drivers/infiniband/sw/rxe/rxe_hw_counters.h | 1 - drivers/infiniband/sw/rxe/rxe_resp.c | 13 +------------ 4 files changed, 2 insertions(+), 25 deletions(-)