[dpdk-dev] [RFC PATCH] timer: inform periodic timers of multiple expiries
Bruce Richardson
bruce.richardson at intel.com
Fri Apr 28 15:25:38 CEST 2017
if timer_manage is called much less frequently than the period of a
periodic timer, then timer expiries will be missed. For example, if a timer
has a period of 300us, but timer_manage is called every 1ms, then there
will only be one timer callback called every 1ms instead of 3 within that
time.
While we can fix this by having each function called multiple times within
timer-manage, this will lead to out-of-order timeouts, and will be slower
with all the function call overheads - especially in the case of a timeout
doing something trivial like incrementing a counter. Therefore, we instead
modify the callback functions to take a counter value of the number of
expiries that have passed since the last time it was called.
Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
---
examples/l2fwd-jobstats/main.c | 7 +++++--
examples/l2fwd-keepalive/main.c | 8 ++++----
examples/l3fwd-power/main.c | 5 +++--
examples/performance-thread/common/lthread_sched.c | 4 +++-
examples/performance-thread/common/lthread_sched.h | 2 +-
examples/timer/main.c | 10 ++++++----
lib/librte_timer/rte_timer.c | 9 ++++++++-
lib/librte_timer/rte_timer.h | 2 +-
test/test/test_timer.c | 14 +++++++++-----
test/test/test_timer_perf.c | 4 +++-
test/test/test_timer_racecond.c | 3 ++-
11 files changed, 45 insertions(+), 23 deletions(-)
diff --git a/examples/l2fwd-jobstats/main.c b/examples/l2fwd-jobstats/main.c
index e6e6c22..b264344 100644
--- a/examples/l2fwd-jobstats/main.c
+++ b/examples/l2fwd-jobstats/main.c
@@ -410,7 +410,8 @@ l2fwd_job_update_cb(struct rte_jobstats *job, int64_t result)
}
static void
-l2fwd_fwd_job(__rte_unused struct rte_timer *timer, void *arg)
+l2fwd_fwd_job(__rte_unused struct rte_timer *timer,
+ __rte_unused unsigned int count, void *arg)
{
struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
struct rte_mbuf *m;
@@ -460,7 +461,9 @@ l2fwd_fwd_job(__rte_unused struct rte_timer *timer, void *arg)
}
static void
-l2fwd_flush_job(__rte_unused struct rte_timer *timer, __rte_unused void *arg)
+l2fwd_flush_job(__rte_unused struct rte_timer *timer,
+ __rte_unused unsigned int count,
+ __rte_unused void *arg)
{
uint64_t now;
unsigned lcore_id;
diff --git a/examples/l2fwd-keepalive/main.c b/examples/l2fwd-keepalive/main.c
index 4623d2a..26eba12 100644
--- a/examples/l2fwd-keepalive/main.c
+++ b/examples/l2fwd-keepalive/main.c
@@ -144,8 +144,9 @@ struct rte_keepalive *rte_global_keepalive_info;
/* Print out statistics on packets dropped */
static void
-print_stats(__attribute__((unused)) struct rte_timer *ptr_timer,
- __attribute__((unused)) void *ptr_data)
+print_stats(__rte_unused struct rte_timer *ptr_timer,
+ __rte_unused unsigned int count,
+ __rte_unused void *ptr_data)
{
uint64_t total_packets_dropped, total_packets_tx, total_packets_rx;
unsigned portid;
@@ -748,8 +749,7 @@ main(int argc, char **argv)
(check_period * rte_get_timer_hz()) / 1000,
PERIODICAL,
rte_lcore_id(),
- (void(*)(struct rte_timer*, void*))
- &rte_keepalive_dispatch_pings,
+ (void *)&rte_keepalive_dispatch_pings,
rte_global_keepalive_info
) != 0 )
rte_exit(EXIT_FAILURE, "Keepalive setup failure.\n");
diff --git a/examples/l3fwd-power/main.c b/examples/l3fwd-power/main.c
index ec40a17..318aefd 100644
--- a/examples/l3fwd-power/main.c
+++ b/examples/l3fwd-power/main.c
@@ -410,8 +410,9 @@ signal_exit_now(int sigtype)
/* Freqency scale down timer callback */
static void
-power_timer_cb(__attribute__((unused)) struct rte_timer *tim,
- __attribute__((unused)) void *arg)
+power_timer_cb(__rte_unused struct rte_timer *tim,
+ __rte_unused unsigned int count,
+ __rte_unused void *arg)
{
uint64_t hz;
float sleep_time_ratio;
diff --git a/examples/performance-thread/common/lthread_sched.c b/examples/performance-thread/common/lthread_sched.c
index c64c21f..c4c7d3b 100644
--- a/examples/performance-thread/common/lthread_sched.c
+++ b/examples/performance-thread/common/lthread_sched.c
@@ -437,7 +437,9 @@ static inline void _lthread_resume(struct lthread *lt)
* Handle sleep timer expiry
*/
void
-_sched_timer_cb(struct rte_timer *tim, void *arg)
+_sched_timer_cb(struct rte_timer *tim,
+ unsigned int count __rte_unused,
+ void *arg)
{
struct lthread *lt = (struct lthread *) arg;
uint64_t state = lt->state;
diff --git a/examples/performance-thread/common/lthread_sched.h b/examples/performance-thread/common/lthread_sched.h
index 7cddda9..f2af8b3 100644
--- a/examples/performance-thread/common/lthread_sched.h
+++ b/examples/performance-thread/common/lthread_sched.h
@@ -149,7 +149,7 @@ _reschedule(void)
}
extern struct lthread_sched *schedcore[];
-void _sched_timer_cb(struct rte_timer *tim, void *arg);
+void _sched_timer_cb(struct rte_timer *tim, unsigned int count, void *arg);
void _sched_shutdown(__rte_unused void *arg);
#ifdef __cplusplus
diff --git a/examples/timer/main.c b/examples/timer/main.c
index 37ad559..92a6a1f 100644
--- a/examples/timer/main.c
+++ b/examples/timer/main.c
@@ -55,8 +55,9 @@ static struct rte_timer timer1;
/* timer0 callback */
static void
-timer0_cb(__attribute__((unused)) struct rte_timer *tim,
- __attribute__((unused)) void *arg)
+timer0_cb(__rte_unused struct rte_timer *tim,
+ __rte_unused unsigned int count,
+ __rte_unused void *arg)
{
static unsigned counter = 0;
unsigned lcore_id = rte_lcore_id();
@@ -71,8 +72,9 @@ timer0_cb(__attribute__((unused)) struct rte_timer *tim,
/* timer1 callback */
static void
-timer1_cb(__attribute__((unused)) struct rte_timer *tim,
- __attribute__((unused)) void *arg)
+timer1_cb(__rte_unused struct rte_timer *tim,
+ __rte_unused unsigned int count,
+ __rte_unused void *arg)
{
unsigned lcore_id = rte_lcore_id();
uint64_t hz;
diff --git a/lib/librte_timer/rte_timer.c b/lib/librte_timer/rte_timer.c
index 18782fa..d1e2c12 100644
--- a/lib/librte_timer/rte_timer.c
+++ b/lib/librte_timer/rte_timer.c
@@ -590,7 +590,14 @@ void rte_timer_manage(void)
priv_timer[lcore_id].running_tim = tim;
/* execute callback function with list unlocked */
- tim->f(tim, tim->arg);
+ if (tim->period == 0)
+ tim->f(tim, 1, tim->arg);
+ else {
+ /* for periodic check how many expiries we have */
+ uint64_t over_time = cur_time - tim->expire;
+ unsigned int extra_expiries = over_time / tim->period;
+ tim->f(tim, 1 + extra_expiries, tim->arg);
+ }
__TIMER_STAT_ADD(pending, -1);
/* the timer was stopped or reloaded by the callback
diff --git a/lib/librte_timer/rte_timer.h b/lib/librte_timer/rte_timer.h
index a276a73..bc434ec 100644
--- a/lib/librte_timer/rte_timer.h
+++ b/lib/librte_timer/rte_timer.h
@@ -117,7 +117,7 @@ struct rte_timer;
/**
* Callback function type for timer expiry.
*/
-typedef void (*rte_timer_cb_t)(struct rte_timer *, void *);
+typedef void (*rte_timer_cb_t)(struct rte_timer *, unsigned int count, void *);
#define MAX_SKIPLIST_DEPTH 10
diff --git a/test/test/test_timer.c b/test/test/test_timer.c
index 2f6525a..0b86d3c 100644
--- a/test/test/test_timer.c
+++ b/test/test/test_timer.c
@@ -153,7 +153,8 @@ struct mytimerinfo {
static struct mytimerinfo mytiminfo[NB_TIMER];
-static void timer_basic_cb(struct rte_timer *tim, void *arg);
+static void
+timer_basic_cb(struct rte_timer *tim, unsigned int count, void *arg);
static void
mytimer_reset(struct mytimerinfo *timinfo, uint64_t ticks,
@@ -167,6 +168,7 @@ mytimer_reset(struct mytimerinfo *timinfo, uint64_t ticks,
/* timer callback for stress tests */
static void
timer_stress_cb(__attribute__((unused)) struct rte_timer *tim,
+ __attribute__((unused)) unsigned int count,
__attribute__((unused)) void *arg)
{
long r;
@@ -293,9 +295,11 @@ static volatile int cb_count = 0;
/* callback for second stress test. will only be called
* on master lcore */
static void
-timer_stress2_cb(struct rte_timer *tim __rte_unused, void *arg __rte_unused)
+timer_stress2_cb(struct rte_timer *tim __rte_unused,
+ unsigned int count,
+ void *arg __rte_unused)
{
- cb_count++;
+ cb_count += count;
}
#define NB_STRESS2_TIMERS 8192
@@ -430,7 +434,7 @@ timer_stress2_main_loop(__attribute__((unused)) void *arg)
/* timer callback for basic tests */
static void
-timer_basic_cb(struct rte_timer *tim, void *arg)
+timer_basic_cb(struct rte_timer *tim, unsigned int count, void *arg)
{
struct mytimerinfo *timinfo = arg;
uint64_t hz = rte_get_timer_hz();
@@ -440,7 +444,7 @@ timer_basic_cb(struct rte_timer *tim, void *arg)
if (rte_timer_pending(tim))
return;
- timinfo->count ++;
+ timinfo->count += count;
RTE_LOG(INFO, TESTTIMER,
"%"PRIu64": callback id=%u count=%u on core %u\n",
diff --git a/test/test/test_timer_perf.c b/test/test/test_timer_perf.c
index fa77efb..5b3867d 100644
--- a/test/test/test_timer_perf.c
+++ b/test/test/test_timer_perf.c
@@ -48,7 +48,9 @@
int outstanding_count = 0;
static void
-timer_cb(struct rte_timer *t __rte_unused, void *param __rte_unused)
+timer_cb(struct rte_timer *t __rte_unused,
+ unsigned int count __rte_unused,
+ void *param __rte_unused)
{
outstanding_count--;
}
diff --git a/test/test/test_timer_racecond.c b/test/test/test_timer_racecond.c
index 7824ec4..b1c5c86 100644
--- a/test/test/test_timer_racecond.c
+++ b/test/test/test_timer_racecond.c
@@ -65,7 +65,8 @@ static volatile unsigned stop_slaves;
static int reload_timer(struct rte_timer *tim);
static void
-timer_cb(struct rte_timer *tim, void *arg __rte_unused)
+timer_cb(struct rte_timer *tim, unsigned int count __rte_unused,
+ void *arg __rte_unused)
{
/* Simulate slow callback function, 100 us. */
rte_delay_us(100);
--
2.9.3
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