From: Idan Horowitz <idan.horow...@gmail.com>
Instead of taking the lock of the cpu work list in order to check if it's
empty, we can just read the head pointer atomically. This decreases
cpu_work_list_empty's share from 5% to 1.3% in a profile of icount-enabled
aarch64-softmmu.
Signed-off-by: Idan Horowitz <idan.horow...@gmail.com>
Message-Id: <20220114004358.299534-1-idan.horow...@gmail.com>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
softmmu/cpus.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/softmmu/cpus.c b/softmmu/cpus.c
index 23bca46b07..035395ae13 100644
--- a/softmmu/cpus.c
+++ b/softmmu/cpus.c
@@ -73,12 +73,7 @@ bool cpu_is_stopped(CPUState *cpu)
bool cpu_work_list_empty(CPUState *cpu)
{
- bool ret;
-
- qemu_mutex_lock(&cpu->work_mutex);
- ret = QSIMPLEQ_EMPTY(&cpu->work_list);
- qemu_mutex_unlock(&cpu->work_mutex);
- return ret;
+ return QSIMPLEQ_EMPTY_ATOMIC(&cpu->work_list);
}
bool cpu_thread_is_idle(CPUState *cpu)
--
2.25.1
