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keepalive: fix state alignment

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The __rte_cache_aligned was applied to the whole array,
not the array elements. This leads to a false sharing between
the monitored cores.

Fixes: e70a61ad50ab ("keepalive: export states")
Cc: stable@dpdk.org

Signed-off-by: Andriy Berestovskyy <aber@semihalf.com>
Acked-by: Remy Horton <remy.horton@intel.com>
This commit is contained in:
Andriy Berestovskyy 2018-01-23 16:43:16 +01:00 committed by Thomas Monjalon
parent 0bf876008f
commit 462d918937
2 changed files with 19 additions and 11 deletions
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2
doc/guides/sample_app_ug/keep_alive.rst
View File

@ -168,5 +168,5 @@ The rte_keepalive_mark_alive function simply sets the core state to alive.
static inline void
rte_keepalive_mark_alive(struct rte_keepalive *keepcfg)
{
keepcfg->state_flags[rte_lcore_id()] = ALIVE;
keepcfg->live_data[rte_lcore_id()].core_state = RTE_KA_STATE_ALIVE;
}

28
lib/librte_eal/common/rte_keepalive.c
View File

@ -13,8 +13,12 @@
struct rte_keepalive {
/** Core Liveness. */
enum rte_keepalive_state __rte_cache_aligned state_flags[
RTE_KEEPALIVE_MAXCORES];
struct {
/*
* Each element must be cache aligned to prevent false sharing.
*/
enum rte_keepalive_state core_state __rte_cache_aligned;
} live_data[RTE_KEEPALIVE_MAXCORES];
/** Last-seen-alive timestamps */
uint64_t last_alive[RTE_KEEPALIVE_MAXCORES];
@ -67,19 +71,22 @@ rte_keepalive_dispatch_pings(__rte_unused void *ptr_timer,
if (keepcfg->active_cores[idx_core] == 0)
continue;
switch (keepcfg->state_flags[idx_core]) {
switch (keepcfg->live_data[idx_core].core_state) {
case RTE_KA_STATE_UNUSED:
break;
case RTE_KA_STATE_ALIVE: /* Alive */
keepcfg->state_flags[idx_core] = RTE_KA_STATE_MISSING;
keepcfg->live_data[idx_core].core_state =
RTE_KA_STATE_MISSING;
keepcfg->last_alive[idx_core] = rte_rdtsc();
break;
case RTE_KA_STATE_MISSING: /* MIA */
print_trace("Core MIA. ", keepcfg, idx_core);
keepcfg->state_flags[idx_core] = RTE_KA_STATE_DEAD;
keepcfg->live_data[idx_core].core_state =
RTE_KA_STATE_DEAD;
break;
case RTE_KA_STATE_DEAD: /* Dead */
keepcfg->state_flags[idx_core] = RTE_KA_STATE_GONE;
keepcfg->live_data[idx_core].core_state =
RTE_KA_STATE_GONE;
print_trace("Core died. ", keepcfg, idx_core);
if (keepcfg->callback)
keepcfg->callback(
@ -90,7 +97,8 @@ rte_keepalive_dispatch_pings(__rte_unused void *ptr_timer,
case RTE_KA_STATE_GONE: /* Buried */
break;
case RTE_KA_STATE_DOZING: /* Core going idle */
keepcfg->state_flags[idx_core] = RTE_KA_STATE_SLEEP;
keepcfg->live_data[idx_core].core_state =
RTE_KA_STATE_SLEEP;
keepcfg->last_alive[idx_core] = rte_rdtsc();
break;
case RTE_KA_STATE_SLEEP: /* Idled core */
@ -100,7 +108,7 @@ rte_keepalive_dispatch_pings(__rte_unused void *ptr_timer,
keepcfg->relay_callback(
keepcfg->relay_callback_data,
idx_core,
keepcfg->state_flags[idx_core],
keepcfg->live_data[idx_core].core_state,
keepcfg->last_alive[idx_core]
);
}
@ -144,11 +152,11 @@ rte_keepalive_register_core(struct rte_keepalive *keepcfg, const int id_core)
void
rte_keepalive_mark_alive(struct rte_keepalive *keepcfg)
{
keepcfg->state_flags[rte_lcore_id()] = RTE_KA_STATE_ALIVE;
keepcfg->live_data[rte_lcore_id()].core_state = RTE_KA_STATE_ALIVE;
}
void
rte_keepalive_mark_sleep(struct rte_keepalive *keepcfg)
{
keepcfg->state_flags[rte_lcore_id()] = RTE_KA_STATE_DOZING;
keepcfg->live_data[rte_lcore_id()].core_state = RTE_KA_STATE_DOZING;
}