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envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::102f; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x102f.google.com X-Spam_score_int: -12 X-Spam_score: -1.3 X-Spam_bar: - X-Spam_report: (-1.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, PDS_HP_HELO_NORDNS=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, Idan Horowitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1644544281992100001 Content-Type: text/plain; charset="utf-8" From: Idan Horowitz 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) =20 bool cpu_work_list_empty(CPUState *cpu) { - bool ret; - - qemu_mutex_lock(&cpu->work_mutex); - ret =3D QSIMPLEQ_EMPTY(&cpu->work_list); - qemu_mutex_unlock(&cpu->work_mutex); - return ret; + return QSIMPLEQ_EMPTY_ATOMIC(&cpu->work_list); } =20 bool cpu_thread_is_idle(CPUState *cpu) --=20 2.25.1