From 25e82fb769eddb83e0b68487b8b08d9426704d54 Mon Sep 17 00:00:00 2001 From: Idan Horowitz Date: Fri, 14 Jan 2022 02:43:57 +0200 Subject: [PATCH] softmmu/cpus: Check if the cpu work list is empty atomically 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 Message-Id: <20220114004358.299534-1-idan.horowitz@gmail.com> Reviewed-by: Richard Henderson Signed-off-by: Richard Henderson --- 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)