diff options
| author | Felipe Franciosi <felipe@nutanix.com> | 2017-05-19 22:29:50 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2017-06-07 18:22:03 +0200 |
| commit | 90bb0c04214545beb75044a2742f711335103269 (patch) | |
| tree | b04906444df0d47afdc93ad612aac4c4a1861d64 /cpus.c | |
| parent | d870cfdea5b5fc7934cacc9786f185d741eab308 (diff) | |
cpus: reset throttle_thread_scheduled after sleep
Currently, the throttle_thread_scheduled flag is reset back to 0 before
sleeping (as part of the throttling logic). Given that throttle_timer
(well, any timer) may tick with a slight delay, it so happens that under
heavy throttling (ie. close or on CPU_THROTTLE_PCT_MAX) the tick may
schedule a further cpu_throttle_thread() work item after the flag reset,
but before the previous sleep completed. This results on the vCPU thread
sleeping continuously for potentially several seconds in a row.
The chances of that happening can be drastically minimised by resetting
the flag after the sleep.
Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Signed-off-by: Malcolm Crossley <malcolm@nutanix.com>
Message-Id: <1495229390-18909-1-git-send-email-felipe@nutanix.com>
Acked-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'cpus.c')
| -rw-r--r-- | cpus.c | 2 |
1 files changed, 1 insertions, 1 deletions
@@ -677,9 +677,9 @@ static void cpu_throttle_thread(CPUState *cpu, run_on_cpu_data opaque) sleeptime_ns = (long)(throttle_ratio * CPU_THROTTLE_TIMESLICE_NS); qemu_mutex_unlock_iothread(); - atomic_set(&cpu->throttle_thread_scheduled, 0); g_usleep(sleeptime_ns / 1000); /* Convert ns to us for usleep call */ qemu_mutex_lock_iothread(); + atomic_set(&cpu->throttle_thread_scheduled, 0); } static void cpu_throttle_timer_tick(void *opaque) |