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examples/l3fwd-power: fix race on interrupt wakeup log

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Currently, the interrupt status notification prevents log spam by
remembering whether previous interrupt wakeup was due to traffic or due
to timeout expiring. However, it is a single variable that can
potentially be accessed from multiple threads, so it is not thread-safe.

Fix it by having per-lcore interrupt status.

Fixes: f4d1e19c29 ("examples/l3fwd-power: add Rx interrupt timeout")
Cc: stable@dpdk.org

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: David Hunt <david.hunt@intel.com>
Tested-by: Xi Zhang <xix.zhang@intel.com>
This commit is contained in:
Anatoly Burakov 2020-10-02 13:07:09 +01:00 committed by David Marchand
parent 79d69c6dcf
commit 317a1da8d6
1 changed files with 12 additions and 7 deletions
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19
examples/l3fwd-power/main.c
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@ -821,20 +821,23 @@ power_freq_scaleup_heuristic(unsigned lcore_id,
* 0 on success
*/
static int
sleep_until_rx_interrupt(int num)
sleep_until_rx_interrupt(int num, int lcore)
{
/*
* we want to track when we are woken up by traffic so that we can go
* back to sleep again without log spamming.
* back to sleep again without log spamming. Avoid cache line sharing
* to prevent threads stepping on each others' toes.
*/
static bool timeout;
static struct {
bool wakeup;
} __rte_cache_aligned status[RTE_MAX_LCORE];
struct rte_epoll_event event[num];
int n, i;
uint16_t port_id;
uint8_t queue_id;
void *data;
if (!timeout) {
if (status[lcore].wakeup) {
RTE_LOG(INFO, L3FWD_POWER,
"lcore %u sleeps until interrupt triggers\n",
rte_lcore_id());
@ -851,7 +854,7 @@ sleep_until_rx_interrupt(int num)
" port %d queue %d\n",
rte_lcore_id(), port_id, queue_id);
}
timeout = n == 0;
status[lcore].wakeup = n != 0;
return 0;
}
@ -1050,7 +1053,8 @@ static int main_intr_loop(__rte_unused void *dummy)
if (intr_en) {
turn_on_off_intr(qconf, 1);
sleep_until_rx_interrupt(
qconf->n_rx_queue);
qconf->n_rx_queue,
lcore_id);
turn_on_off_intr(qconf, 0);
/**
* start receiving packets immediately
@ -1473,7 +1477,8 @@ main_legacy_loop(__rte_unused void *dummy)
if (intr_en) {
turn_on_off_intr(qconf, 1);
sleep_until_rx_interrupt(
qconf->n_rx_queue);
qconf->n_rx_queue,
lcore_id);
turn_on_off_intr(qconf, 0);
/**
* start receiving packets immediately