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.horowitz@gmail.com>
Message-Id: <
20220114004358.299534-1-idan.horowitz@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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)