mirror/haproxy
1
0
Fork 0
mirror of http://git.haproxy.org/git/haproxy.git synced 2026-02-17 19:26:55 +02:00
Code Issues Packages Projects Releases Wiki Activity

MINOR: sched: add TASK_F_WANTS_TIME to make the scheduler update the call date

Browse Source 
Currently tasks being profiled have th_ctx->sched_call_date set to the
current nanosecond in monotonic time. But there's no other way to have
this, despite the scheduler being capable of it. Let's just declare a
new task flag, TASK_F_WANTS_TIME, that makes the scheduler take the time
just before calling the handler. This way, a task that needs nanosecond
resolution on the call date will be able to be called with an up-to-date
date without having to abuse now_mono_time() if not needed. In addition,
if CLOCK_MONOTONIC is not supported (now_mono_time() always returns 0),
the date is set to the most recently known now_ns, which is guaranteed
to be atomic and is only updated once per poll loop.

This date can be more conveniently retrieved using task_mono_time().

This can be useful, e.g. for pacing. The code was slightly adjusted so
as to merge the common parts between the profiling case and this one.
This commit is contained in:
Willy Tarreau
2024-11-19 16:27:46 +01:00
parent 12969c1b17
commit c5052bad8a
3 changed files with 22 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
src/task.c
View File

@@ -567,17 +567,24 @@ unsigned int run_tasks_from_lists(unsigned int budgets[])
t->calls++;
th_ctx->sched_wake_date = t->wake_date;
if (th_ctx->sched_wake_date) {
uint32_t now_ns = now_mono_time();
uint32_t lat = now_ns - th_ctx->sched_wake_date;
if (th_ctx->sched_wake_date || (t->state & TASK_F_WANTS_TIME)) {
/* take the most accurate clock we have, either
* mono_time() or last now_ns (monotonic but only
* incremented once per poll loop).
*/
th_ctx->sched_call_date = now_mono_time();
if (unlikely(!th_ctx->sched_call_date))
th_ctx->sched_call_date = now_ns;
}
if (th_ctx->sched_wake_date) {
t->wake_date = 0;
th_ctx->sched_call_date = now_ns;
profile_entry = sched_activity_entry(sched_activity, t->process, t->caller);
th_ctx->sched_profile_entry = profile_entry;
HA_ATOMIC_ADD(&profile_entry->lat_time, lat);
HA_ATOMIC_ADD(&profile_entry->lat_time, (uint32_t)(th_ctx->sched_call_date - th_ctx->sched_wake_date));
HA_ATOMIC_INC(&profile_entry->calls);
}
__ha_barrier_store();
th_ctx->current = t;