From patchwork Tue Dec 8 09:10:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 11958109 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CF59C433FE for ; Tue, 8 Dec 2020 09:12:30 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8EAAF23A7F for ; Tue, 8 Dec 2020 09:12:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8EAAF23A7F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=ispras.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46158 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kmZ2q-0005yg-Cv for qemu-devel@archiver.kernel.org; Tue, 08 Dec 2020 04:12:28 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:41230) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kmZ1e-0004vq-I1 for qemu-devel@nongnu.org; Tue, 08 Dec 2020 04:11:15 -0500 Received: from mail.ispras.ru ([83.149.199.84]:48298) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kmZ1X-0003hJ-Bf for qemu-devel@nongnu.org; Tue, 08 Dec 2020 04:11:14 -0500 Received: from [127.0.1.1] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 9147340A1DA3; Tue, 8 Dec 2020 09:10:58 +0000 (UTC) Subject: [PATCH] icount: improve exec nocache usage From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Tue, 08 Dec 2020 12:10:58 +0300 Message-ID: <160741865825.348476.7169239332367828943.stgit@pasha-ThinkPad-X280> User-Agent: StGit/0.23 MIME-Version: 1.0 Received-SPF: pass client-ip=83.149.199.84; envelope-from=pavel.dovgalyuk@ispras.ru; helo=mail.ispras.ru X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alex.bennee@linaro.org, pbonzini@redhat.com, pavel.dovgalyuk@ispras.ru Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" cpu-exec tries to execute TB without caching when current icount budget is over. But sometimes refilled budget is big enough to try executing cached blocks. This patch checks that instruction budget is big enough for next block execution instead of just running cpu_exec_nocache. It halves the number of calls of cpu_exec_nocache function during tested OS boot scenario. Signed-off-by: Pavel Dovgalyuk Reviewed-by: Richard Henderson --- accel/tcg/cpu-exec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index 58aea605d8..251b340fb9 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -685,7 +685,7 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb, insns_left = MIN(0xffff, cpu->icount_budget); cpu_neg(cpu)->icount_decr.u16.low = insns_left; cpu->icount_extra = cpu->icount_budget - insns_left; - if (!cpu->icount_extra) { + if (!cpu->icount_extra && insns_left < tb->icount) { /* Execute any remaining instructions, then let the main loop * handle the next event. */