From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
"stephen@networkplumber.org" <stephen@networkplumber.org>,
"Medvedkin, Vladimir" <vladimir.medvedkin@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
Ruifeng Wang <Ruifeng.Wang@arm.com>,
Dharmik Thakkar <Dharmik.Thakkar@arm.com>, nd <nd@arm.com>,
nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH v4 1/4] lib/rcu: add resource reclamation APIs
Date: Mon, 20 Apr 2020 08:19:41 +0000 [thread overview]
Message-ID: <BYAPR11MB33019D038A45E7B66C43CB7C9AD40@BYAPR11MB3301.namprd11.prod.outlook.com> (raw)
In-Reply-To: <DBBPR08MB4646A86601E0DCD4C34A52E598D70@DBBPR08MB4646.eurprd08.prod.outlook.com>
> > > +
> > > + /* Enqueue the token and resource. Generating the token
> > > + * and enqueuing (token + resource) on the queue is not an
> > > + * atomic operation. This might result in tokens enqueued
> > > + * out of order on the queue. So, some tokens might wait
> > > + * longer than they are required to be reclaimed.
> > > + */
> > > + char data[dq->esize];
> > > + memcpy(data, &token, __RTE_QSBR_TOKEN_SIZE);
> > > + memcpy(data + __RTE_QSBR_TOKEN_SIZE, e,
> > > + dq->esize - __RTE_QSBR_TOKEN_SIZE);
> > > + /* Check the status as enqueue might fail since the other thread
> > > + * might have used up the freed space.
> > > + * Enqueue uses the configured flags when the DQ was created.
> > > + */
> > > + if (rte_ring_enqueue_elem(dq->r, data, dq->esize) != 0) {
> > > + rte_log(RTE_LOG_ERR, rte_rcu_log_type,
> > > + "%s(): Enqueue failed\n", __func__);
> > > + /* Note that the token generated above is not used.
> > > + * Other than wasting tokens, it should not cause any
> > > + * other issues.
> > > + */
> > > + rte_log(RTE_LOG_INFO, rte_rcu_log_type,
> > > + "%s(): Skipped enqueuing token = %"PRIu64"\n",
> > > + __func__, token);
> > > +
> > > + rte_errno = ENOSPC;
> > > + return 1;
> > > + }
> >
> >
> > Just as a thought: in theory if we'll use MP_HTS(/SP) ring we can avoid
> > wasting RCU tokens:
> >
> > if (rte_ring_enqueue_elem_bulk_start(dq->r, 1, NULL) != 0) {
> > token = rte_rcu_qsbr_start(dq->v);
> > memcpy(data, &token, __RTE_QSBR_TOKEN_SIZE);
> > rte_ring_enqueue_elem_finish(dq->r, data, dq->esize, 1); }
> >
> > Though it might slowdown things if we'll have a lot of parallel dq_enqueue.
> > So not sure is it worth it or not.
> Adding peek APIs for RTS would be better. That should take care of the parallel dw_enqueue. Not sure if I gave you the comment. My ring
> patch supported these APIs.
AFAIK, peek API is not possible for RTS mode.
Probably you are talking about Scatter-Gather API introduced in your RFC
(_reserve_; update ring entries manually; _commit_)?
Anyway, if there is no much value in my idea above, then feel free to drop it.
>
> >
> > > +
> > > + rte_log(RTE_LOG_INFO, rte_rcu_log_type,
> > > + "%s(): Enqueued token = %"PRIu64"\n", __func__, token);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/* Reclaim resources from the defer queue. */ int
> > > +rte_rcu_qsbr_dq_reclaim(struct rte_rcu_qsbr_dq *dq, unsigned int n,
> > > + unsigned int *freed, unsigned int *pending) {
> > > + uint32_t cnt;
> > > + uint64_t token;
> > > +
> > > + if (dq == NULL || n == 0) {
> > > + rte_log(RTE_LOG_ERR, rte_rcu_log_type,
> > > + "%s(): Invalid input parameter\n", __func__);
> > > + rte_errno = EINVAL;
> > > +
> > > + return 1;
> > > + }
> > > +
> > > + cnt = 0;
> > > +
> > > + char e[dq->esize];
> > > + /* Check reader threads quiescent state and reclaim resources */
> > > + while ((cnt < n) &&
> > > + (rte_ring_dequeue_bulk_elem_start(dq->r, e,
> > > + dq->esize, 1, NULL) != 0)) {
> >
> > Another thought - any point to use burst_elem_start() here to retrieve more
> > then 1 elem in one go? Something like:
> I think it makes sense.
>
> > char e[32][dq->size];
> > while ((cnt < n) {
> > k = RTE_MAX(32, cnt - n);
> > k = rte_ring_dequeue_burst_elem_start(dq->r, e, dq->esize, k, NULL);
> > if (k = 0)
> > break;
> > for (i = 0; i != k; i++) {
> > memcpy(&token, e[i], sizeof(uint64_t));
> > if (rte_rcu_qsbr_check(dq->v, token, false) != 1)
> > break;
> > }
> > k = i;
> > rte_ring_dequeue_elem_finish(dq->r, k);
> > for (i = 0; i != k; i++)
> > dq->free_fn(dq->p, e[i] + __RTE_QSBR_TOKEN_SIZE);
> I think it also makes sense to change the free_fn to take 'n' number of tokens.
>
> > n += k;
> > if (k == 0)
> > break;
> >
> > ?
> > Also if at enqueue we guarantee strict ordrer (via
> > enqueue_start/enqueue_finish), then here we probably can do _check_ from
> > the last retrieved token here?
> > In theory that might help to minimize number of checks.
> > I.E. do:
> > for (i = k; i-- !=0; ) {
> > memcpy(&token, e[i], sizeof(uint64_t));
> > if (rte_rcu_qsbr_check(dq->v, token, false) != 1)
> There is a higher chance that later tokens are not acked. This introduces more polling of the counters.
> The rte_rcu_qsbr_check has an optimization. While acking the current token, it will also caches the greatest token acked. It uses the cached
> token for the subsequent calls. I think this provides a better optimization.
Ok.
next prev parent reply other threads:[~2020-04-20 8:19 UTC|newest]
Thread overview: 137+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-22 6:34 [dpdk-dev] [RFC PATCH 0/3] RCU integration with LPM library Ruifeng Wang
2019-08-22 6:34 ` [dpdk-dev] [RFC PATCH 1/3] doc/rcu: add RCU integration design details Ruifeng Wang
2019-08-22 6:34 ` [dpdk-dev] [RFC PATCH 2/3] lib/ring: add peek API Ruifeng Wang
2019-08-22 6:34 ` [dpdk-dev] [RFC PATCH 3/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2019-08-23 1:23 ` Stephen Hemminger
2019-08-26 3:11 ` Ruifeng Wang (Arm Technology China)
2019-08-26 5:32 ` Honnappa Nagarahalli
2019-08-22 15:52 ` [dpdk-dev] [RFC PATCH 0/3] RCU integration with LPM library Honnappa Nagarahalli
2019-09-06 9:45 ` [dpdk-dev] [PATCH v2 0/6] " Ruifeng Wang
2019-09-06 9:45 ` [dpdk-dev] [PATCH v2 1/6] doc/rcu: add RCU integration design details Ruifeng Wang
2019-09-06 19:44 ` Honnappa Nagarahalli
2019-09-06 9:45 ` [dpdk-dev] [PATCH v2 2/6] lib/ring: add peek API Ruifeng Wang
2019-09-06 9:45 ` [dpdk-dev] [PATCH v2 3/6] lib/lpm: integrate RCU QSBR Ruifeng Wang
2019-09-06 19:44 ` Honnappa Nagarahalli
2019-09-18 16:15 ` Medvedkin, Vladimir
2019-09-19 6:17 ` Ruifeng Wang (Arm Technology China)
2019-09-06 9:45 ` [dpdk-dev] [PATCH v2 4/6] app/test: add test case for LPM RCU integration Ruifeng Wang
2019-09-06 19:45 ` Honnappa Nagarahalli
2019-09-06 9:45 ` [dpdk-dev] [PATCH v2 5/6] test/lpm: reset total time Ruifeng Wang
2019-09-18 16:17 ` Medvedkin, Vladimir
2019-09-19 6:22 ` Ruifeng Wang (Arm Technology China)
2019-09-06 9:45 ` [dpdk-dev] [PATCH v2 6/6] test/lpm: add RCU integration performance tests Ruifeng Wang
2019-09-06 19:46 ` Honnappa Nagarahalli
2019-10-01 6:29 ` [dpdk-dev] [PATCH v3 0/3] Add RCU reclamation APIs Honnappa Nagarahalli
2019-10-01 6:29 ` [dpdk-dev] [PATCH v3 1/3] lib/ring: add peek API Honnappa Nagarahalli
2019-10-02 18:42 ` Ananyev, Konstantin
2019-10-03 19:49 ` Honnappa Nagarahalli
2019-10-07 9:01 ` Ananyev, Konstantin
2019-10-09 4:25 ` Honnappa Nagarahalli
2019-10-10 15:09 ` Ananyev, Konstantin
2019-10-11 5:03 ` Honnappa Nagarahalli
2019-10-11 14:41 ` Ananyev, Konstantin
2019-10-11 18:28 ` Honnappa Nagarahalli
2019-10-13 20:09 ` Ananyev, Konstantin
2019-10-14 4:11 ` Honnappa Nagarahalli
2019-10-01 6:29 ` [dpdk-dev] [PATCH v3 2/3] lib/rcu: add resource reclamation APIs Honnappa Nagarahalli
2019-10-02 17:39 ` Ananyev, Konstantin
2019-10-03 6:29 ` Honnappa Nagarahalli
2019-10-03 12:26 ` Ananyev, Konstantin
2019-10-04 6:07 ` Honnappa Nagarahalli
2019-10-07 10:46 ` Ananyev, Konstantin
2019-10-13 4:35 ` Honnappa Nagarahalli
2019-10-02 18:50 ` Ananyev, Konstantin
2019-10-03 6:42 ` Honnappa Nagarahalli
2019-10-03 11:52 ` Ananyev, Konstantin
2019-10-04 19:01 ` Medvedkin, Vladimir
2019-10-07 13:11 ` Medvedkin, Vladimir
2019-10-13 3:02 ` Honnappa Nagarahalli
2019-10-15 16:48 ` Medvedkin, Vladimir
2019-10-18 3:47 ` Honnappa Nagarahalli
2019-10-01 6:29 ` [dpdk-dev] [PATCH v3 3/3] doc/rcu: add RCU integration design details Honnappa Nagarahalli
2020-03-29 20:57 ` [dpdk-dev] [PATCH v3 0/3] Add RCU reclamation APIs Thomas Monjalon
2020-03-30 17:37 ` Honnappa Nagarahalli
2020-04-03 18:41 ` [dpdk-dev] [PATCH v4 0/4] " Honnappa Nagarahalli
2020-04-03 18:41 ` [dpdk-dev] [PATCH v4 1/4] lib/rcu: add resource " Honnappa Nagarahalli
2020-04-07 17:39 ` Ananyev, Konstantin
2020-04-19 23:22 ` Honnappa Nagarahalli
2020-04-20 8:19 ` Ananyev, Konstantin [this message]
2020-04-03 18:41 ` [dpdk-dev] [PATCH v4 2/4] test/rcu: test cases for RCU defer queue APIs Honnappa Nagarahalli
2020-04-03 18:41 ` [dpdk-dev] [PATCH v4 3/4] doc/rcu: add RCU integration design details Honnappa Nagarahalli
2020-04-03 18:41 ` [dpdk-dev] [PATCH v4 4/4] lib/rcu: add additional debug logs Honnappa Nagarahalli
2020-04-22 3:30 ` [dpdk-dev] [PATCH v5 0/4] Add RCU reclamation APIs Honnappa Nagarahalli
2020-04-22 3:30 ` [dpdk-dev] [PATCH v5 1/4] lib/rcu: add resource " Honnappa Nagarahalli
2020-04-22 8:36 ` Ananyev, Konstantin
2020-04-22 8:42 ` David Marchand
2020-04-22 8:51 ` David Marchand
2020-04-22 9:26 ` Ananyev, Konstantin
2020-04-22 3:30 ` [dpdk-dev] [PATCH v5 2/4] test/rcu: test cases for RCU defer queue APIs Honnappa Nagarahalli
2020-04-22 8:27 ` Ananyev, Konstantin
2020-04-22 3:30 ` [dpdk-dev] [PATCH v5 3/4] doc/rcu: add RCU integration design details Honnappa Nagarahalli
2020-04-22 3:30 ` [dpdk-dev] [PATCH v5 4/4] lib/rcu: add additional debug logs Honnappa Nagarahalli
2020-04-22 8:25 ` Ananyev, Konstantin
2020-04-22 18:46 ` [dpdk-dev] [PATCH v5 0/4] Add RCU reclamation APIs David Marchand
2019-10-01 18:28 ` [dpdk-dev] [PATCH v3 0/3] RCU integration with LPM library Honnappa Nagarahalli
2019-10-01 18:28 ` [dpdk-dev] [PATCH v3 1/3] lib/lpm: integrate RCU QSBR Honnappa Nagarahalli
2019-10-04 16:05 ` Medvedkin, Vladimir
2019-10-09 3:48 ` Honnappa Nagarahalli
2019-10-07 9:21 ` Ananyev, Konstantin
2019-10-13 4:36 ` Honnappa Nagarahalli
2019-10-15 11:15 ` Ananyev, Konstantin
2019-10-18 3:32 ` Honnappa Nagarahalli
2019-10-01 18:28 ` [dpdk-dev] [PATCH v3 2/3] app/test: add test case for LPM RCU integration Honnappa Nagarahalli
2019-10-01 18:28 ` [dpdk-dev] [PATCH v3 3/3] test/lpm: add RCU integration performance tests Honnappa Nagarahalli
2019-10-02 13:02 ` Aaron Conole
2019-10-03 9:09 ` Bruce Richardson
2020-06-08 5:16 ` [dpdk-dev] [PATCH v4 0/3] RCU integration with LPM library Ruifeng Wang
2020-06-08 5:16 ` [dpdk-dev] [PATCH v4 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-06-08 18:46 ` Honnappa Nagarahalli
2020-06-18 17:36 ` Medvedkin, Vladimir
2020-06-18 17:21 ` Medvedkin, Vladimir
2020-06-22 5:46 ` Ruifeng Wang
2020-06-23 4:34 ` Honnappa Nagarahalli
2020-06-08 5:16 ` [dpdk-dev] [PATCH v4 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-06-08 5:16 ` [dpdk-dev] [PATCH v4 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-06-29 8:02 ` [dpdk-dev] [PATCH v5 0/3] RCU integration with LPM library Ruifeng Wang
2020-06-29 8:02 ` [dpdk-dev] [PATCH v5 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-06-29 11:56 ` David Marchand
2020-06-29 12:55 ` Bruce Richardson
2020-06-30 10:35 ` Kinsella, Ray
2020-07-03 7:43 ` David Marchand
2020-07-04 17:00 ` Ruifeng Wang
2020-06-30 10:33 ` Kinsella, Ray
2020-06-29 8:02 ` [dpdk-dev] [PATCH v5 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-06-29 8:03 ` [dpdk-dev] [PATCH v5 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-07 14:40 ` [dpdk-dev] [PATCH v6 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-07 14:40 ` [dpdk-dev] [PATCH v6 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-07 14:40 ` [dpdk-dev] [PATCH v6 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-07 14:40 ` [dpdk-dev] [PATCH v6 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-07 15:15 ` [dpdk-dev] [PATCH v7 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-07 15:15 ` [dpdk-dev] [PATCH v7 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-08 12:36 ` Medvedkin, Vladimir
2020-07-08 14:30 ` David Marchand
2020-07-08 15:34 ` Ruifeng Wang
2020-07-07 15:15 ` [dpdk-dev] [PATCH v7 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-08 12:37 ` Medvedkin, Vladimir
2020-07-08 14:00 ` Ruifeng Wang
2020-07-07 15:15 ` [dpdk-dev] [PATCH v7 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-08 12:37 ` Medvedkin, Vladimir
2020-07-08 14:07 ` Ruifeng Wang
2020-07-09 8:02 ` [dpdk-dev] [PATCH v8 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-09 8:02 ` [dpdk-dev] [PATCH v8 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-09 11:49 ` David Marchand
2020-07-09 14:35 ` Ruifeng Wang
2020-07-09 8:02 ` [dpdk-dev] [PATCH v8 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-09 8:02 ` [dpdk-dev] [PATCH v8 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-09 15:42 ` [dpdk-dev] [PATCH v9 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-09 15:42 ` [dpdk-dev] [PATCH v9 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-09 15:42 ` [dpdk-dev] [PATCH v9 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-09 15:42 ` [dpdk-dev] [PATCH v9 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-10 2:22 ` [dpdk-dev] [PATCH v10 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-10 2:22 ` [dpdk-dev] [PATCH v10 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-10 2:29 ` Ruifeng Wang
2020-07-10 2:22 ` [dpdk-dev] [PATCH v10 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-10 2:22 ` [dpdk-dev] [PATCH v10 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-10 2:29 ` Ruifeng Wang
2020-07-10 12:21 ` [dpdk-dev] [PATCH v10 0/3] RCU integration with LPM library David Marchand
2020-07-10 14:34 ` Ruifeng Wang
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