From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 50373C072B5 for ; Fri, 24 May 2019 11:16:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 279EC21773 for ; Fri, 24 May 2019 11:16:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="twWc4/+Q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390971AbfEXLQp (ORCPT ); Fri, 24 May 2019 07:16:45 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:40051 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390410AbfEXLQl (ORCPT ); Fri, 24 May 2019 07:16:41 -0400 Received: by mail-wr1-f66.google.com with SMTP id t4so1326384wrx.7 for ; Fri, 24 May 2019 04:16:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=L7Wy/UoR346yun6rGdrn0w0Sk7Zt+3JLoV24BHUfklw=; b=twWc4/+Qzxo/D1UOnToCY0eDa73j5l1K8Qp94mmxWXgleAnqOFh7FoKKZXgEX4YCZ0 k2+yDABe/dRSA4VkRLWycdfvXMNAh72chSlPqCET2BGRhVfJyuoVFeS8WwFTy7HwZ5LZ RHnk8bGliEfW33uzlNY+eHQRjzpwMaHQtca8eb9UsIl+QVPTpYk0CQDqCU8rAZQL+VCQ jIEpo5lLqbJeJcRRObCrX2EcluaWMkAhvFRcRKq0/9bjxxpX1u2WV6zE+8uh2LN2M9Lr 57VthcvkM2QDAh+/7dH2ni5xz4/7svNg+4NpIlS7Md0oowPzqWjkGBq9JjBEZSOqfKy7 JRNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=L7Wy/UoR346yun6rGdrn0w0Sk7Zt+3JLoV24BHUfklw=; b=BSZtwcg4XluQ7viQ4XtYkCMRR+pZBDGs6broLnFyYVZOxRfKGJU05aNpYeQhZrBbDJ IOdne5850jWKU/EMSHt3FT7t55FTGrfQM6sseI2S0Ns0tFfRwvOD7iNuMNbofWU7JzEG m77FeVdJZdA/WAHZCLyTjKgvvtDFQVCAQiAF992GEfQWj6XXpyalcqS5cpb7tSnFHCXH ocM3hKZiHKjIY5MEQAgYCcjUC+DwFZvhCPNOtIiYQv2qXRogTxhroQYsQdzEw4rMh3ZC CSaW7SYHG7MRz8qFDJZTDQKc3FxJ782tQYfDPQLzUg2O/ZTlARBtwK36AzjkL9E2uSm2 Sm2g== X-Gm-Message-State: APjAAAVQtPmAUCddQQPr33+EQuFaTbS9jAcWkyNEGdLagc3N0UhPmKnl nz0vrIoGANNnr3prAZP2NUuwmw== X-Google-Smtp-Source: APXvYqw/r6MOQUm7yL1/YotNmLwatMoacJjTUqbMZk2z6ica/A8ndWWmfGDLMbPOl6S4ZfvHpN/7yQ== X-Received: by 2002:adf:e94b:: with SMTP id m11mr5174901wrn.133.1558696600480; Fri, 24 May 2019 04:16:40 -0700 (PDT) Received: from clegane.local (73.82.95.92.rev.sfr.net. [92.95.82.73]) by smtp.gmail.com with ESMTPSA id h12sm2575392wre.14.2019.05.24.04.16.39 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 May 2019 04:16:39 -0700 (PDT) From: Daniel Lezcano To: tglx@linutronix.de Cc: linux-kernel@vger.kernel.org, andriy.shevchenko@linux.intel.com Subject: [PATCH V2 3/9] genirq/timings: Optimize the period detection speed Date: Fri, 24 May 2019 13:16:09 +0200 Message-Id: <20190524111615.4891-4-daniel.lezcano@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190524111615.4891-1-daniel.lezcano@linaro.org> References: <20190524111615.4891-1-daniel.lezcano@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we have a minimal period and if there is a period which is a multiple of it but lesser than the max period then it will be detected before and the minimal period will be never reached. 1 2 1 2 1 2 1 2 1 2 1 2 <-----> <-----> <-----> <-> <-> <-> <-> <-> <-> In our case, the minimum period is 2 and the maximum period is 5. That means all repeating pattern of 2 will be detected as repeating pattern of 4, it is pointless to go up to 2 when searching for the period as it will always fail. Remove one loop iteration by increasing the minimal period to 3. Signed-off-by: Daniel Lezcano --- kernel/irq/timings.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/irq/timings.c b/kernel/irq/timings.c index 250bb00ccd85..06bde5253a7d 100644 --- a/kernel/irq/timings.c +++ b/kernel/irq/timings.c @@ -261,7 +261,7 @@ void irq_timings_disable(void) #define EMA_ALPHA_VAL 64 #define EMA_ALPHA_SHIFT 7 -#define PREDICTION_PERIOD_MIN 2 +#define PREDICTION_PERIOD_MIN 3 #define PREDICTION_PERIOD_MAX 5 #define PREDICTION_FACTOR 4 #define PREDICTION_MAX 10 /* 2 ^ PREDICTION_MAX useconds */ -- 2.17.1