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From: Phil Yang <phil.yang@arm.com>
To: thomas@monjalon.net, harry.van.haaren@intel.com,
konstantin.ananyev@intel.com, stephen@networkplumber.org,
maxime.coquelin@redhat.com, dev@dpdk.org
Cc: david.marchand@redhat.com, jerinj@marvell.com, hemant.agrawal@nxp.com,
Honnappa.Nagarahalli@arm.com, gavin.hu@arm.com, ruifeng.wang@arm.com,
joyce.kong@arm.com, nd@arm.com
Date: Thu, 12 Mar 2020 15:44:31 +0800
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<1583999071-22872-1-git-send-email-phil.yang@arm.com>
Subject: [dpdk-dev] [PATCH v2 10/10] service: relax barriers with C11 atomic
operations
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To guarantee the inter-threads visibility of the shareable domain, it
uses a lot of rte_smp_r/wmb in the service library. This patch relaxed
these barriers for service by using c11 atomic one-way barrier operations.
Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Reviewed-by: Gavin Hu <gavin.hu@arm.com>
---
lib/librte_eal/common/rte_service.c | 45 ++++++++++++++++++++-----------------
1 file changed, 25 insertions(+), 20 deletions(-)
diff --git a/lib/librte_eal/common/rte_service.c b/lib/librte_eal/common/rte_service.c
index 96a59b6..9c02c24 100644
--- a/lib/librte_eal/common/rte_service.c
+++ b/lib/librte_eal/common/rte_service.c
@@ -176,9 +176,11 @@ rte_service_set_stats_enable(uint32_t id, int32_t enabled)
SERVICE_VALID_GET_OR_ERR_RET(id, s, 0);
if (enabled)
- s->internal_flags |= SERVICE_F_STATS_ENABLED;
+ __atomic_or_fetch(&s->internal_flags, SERVICE_F_STATS_ENABLED,
+ __ATOMIC_RELEASE);
else
- s->internal_flags &= ~(SERVICE_F_STATS_ENABLED);
+ __atomic_and_fetch(&s->internal_flags,
+ ~(SERVICE_F_STATS_ENABLED), __ATOMIC_RELEASE);
return 0;
}
@@ -190,9 +192,11 @@ rte_service_set_runstate_mapped_check(uint32_t id, int32_t enabled)
SERVICE_VALID_GET_OR_ERR_RET(id, s, 0);
if (enabled)
- s->internal_flags |= SERVICE_F_START_CHECK;
+ __atomic_or_fetch(&s->internal_flags, SERVICE_F_START_CHECK,
+ __ATOMIC_RELEASE);
else
- s->internal_flags &= ~(SERVICE_F_START_CHECK);
+ __atomic_and_fetch(&s->internal_flags, ~(SERVICE_F_START_CHECK),
+ __ATOMIC_RELEASE);
return 0;
}
@@ -261,8 +265,8 @@ rte_service_component_register(const struct rte_service_spec *spec,
s->spec = *spec;
s->internal_flags |= SERVICE_F_REGISTERED | SERVICE_F_START_CHECK;
- rte_smp_wmb();
- rte_service_count++;
+ /* make sure the counter update after the state change. */
+ __atomic_add_fetch(&rte_service_count, 1, __ATOMIC_RELEASE);
if (id_ptr)
*id_ptr = free_slot;
@@ -278,9 +282,10 @@ rte_service_component_unregister(uint32_t id)
SERVICE_VALID_GET_OR_ERR_RET(id, s, -EINVAL);
rte_service_count--;
- rte_smp_wmb();
- s->internal_flags &= ~(SERVICE_F_REGISTERED);
+ /* make sure the counter update before the state change. */
+ __atomic_and_fetch(&s->internal_flags, ~(SERVICE_F_REGISTERED),
+ __ATOMIC_RELEASE);
/* clear the run-bit in all cores */
for (i = 0; i < RTE_MAX_LCORE; i++)
@@ -298,11 +303,12 @@ rte_service_component_runstate_set(uint32_t id, uint32_t runstate)
SERVICE_VALID_GET_OR_ERR_RET(id, s, -EINVAL);
if (runstate)
- s->comp_runstate = RUNSTATE_RUNNING;
+ __atomic_store_n(&s->comp_runstate, RUNSTATE_RUNNING,
+ __ATOMIC_RELEASE);
else
- s->comp_runstate = RUNSTATE_STOPPED;
+ __atomic_store_n(&s->comp_runstate, RUNSTATE_STOPPED,
+ __ATOMIC_RELEASE);
- rte_smp_wmb();
return 0;
}
@@ -313,11 +319,12 @@ rte_service_runstate_set(uint32_t id, uint32_t runstate)
SERVICE_VALID_GET_OR_ERR_RET(id, s, -EINVAL);
if (runstate)
- s->app_runstate = RUNSTATE_RUNNING;
+ __atomic_store_n(&s->app_runstate, RUNSTATE_RUNNING,
+ __ATOMIC_RELEASE);
else
- s->app_runstate = RUNSTATE_STOPPED;
+ __atomic_store_n(&s->app_runstate, RUNSTATE_STOPPED,
+ __ATOMIC_RELEASE);
- rte_smp_wmb();
return 0;
}
@@ -439,7 +446,8 @@ service_runner_func(void *arg)
const int lcore = rte_lcore_id();
struct core_state *cs = &lcore_states[lcore];
- while (lcore_states[lcore].runstate == RUNSTATE_RUNNING) {
+ while (__atomic_load_n(&cs->runstate,
+ __ATOMIC_ACQUIRE) == RUNSTATE_RUNNING) {
const uint64_t service_mask = cs->service_mask;
for (i = 0; i < RTE_SERVICE_NUM_MAX; i++) {
@@ -450,8 +458,6 @@ service_runner_func(void *arg)
}
cs->loops++;
-
- rte_smp_rmb();
}
lcore_config[lcore].state = WAIT;
@@ -660,9 +666,8 @@ rte_service_lcore_add(uint32_t lcore)
/* ensure that after adding a core the mask and state are defaults */
lcore_states[lcore].service_mask = 0;
- lcore_states[lcore].runstate = RUNSTATE_STOPPED;
-
- rte_smp_wmb();
+ __atomic_store_n(&lcore_states[lcore].runstate, RUNSTATE_STOPPED,
+ __ATOMIC_RELEASE);
return rte_eal_wait_lcore(lcore);
}
--
2.7.4