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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20125C77B7F for ; Fri, 5 May 2023 09:09:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231587AbjEEJJn (ORCPT ); Fri, 5 May 2023 05:09:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231611AbjEEJJe (ORCPT ); Fri, 5 May 2023 05:09:34 -0400 Received: from mail-ed1-x52a.google.com (mail-ed1-x52a.google.com [IPv6:2a00:1450:4864:20::52a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC0BE18DE9 for ; Fri, 5 May 2023 02:09:32 -0700 (PDT) Received: by mail-ed1-x52a.google.com with SMTP id 4fb4d7f45d1cf-50bc5197d33so2868136a12.1 for ; Fri, 05 May 2023 02:09:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1683277771; x=1685869771; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=Jk1DeIVD6aFFUK+hNctD6yXAEyZEjJLVTe/neBKRhIY=; b=jvrwp9mhWR1wGFxOJwjAl/pdhYYzCxyUk8PoYVhPQccwp1nAGcO51/C6zUli7auMGw c0HM3n1GJjFAbAapsfDDLt95A+XJUadNvXIC35gmlHsPVUUZZkh7qCYyEIxZuDExF26H NBCO1HamoDJIwMO8IHRoxJiHNSNG/jmFbNJLrFwNw5AheNAdZzsiqGm5LjJG/2y56UNV huJ0eukgei4iUw+lBpo885iTl79hyGeaJUVGuS9BO4zMD2O3Ad1nOTeE2bQ9yfk0qRii xDVwHDU3xv+Uy1YKF1kb5CSA+N7H1qTdggAz2okwkUmkjuwr+Cx5pzpiPQDQP9Axarwq 4Ryw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683277771; x=1685869771; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Jk1DeIVD6aFFUK+hNctD6yXAEyZEjJLVTe/neBKRhIY=; b=TlXV2oSHa93oPLVGHlNKEmdRhjV4febqMqCF9RairzQus0l93arW2JngjHYdXRFXuY 2E9ZEuZXbYDUjBb+/ypFx+f1e+/4t0q8ioGTOyDMrla2b3WDwrUedeu3QtAK8BKOFnDK zFEez3yWdTdwZk0XRQRPgWioF6M8VDtjTrl8C3YiuZ/4Bv9Ytub+rycCIvl6mQ8Y2B9J MRmheuaMFel2B8P0CcGmmDvgQZ7ab6rDmsahvAgkgKy757qJ9iOo+txn2uex69fE/sKx BC7lAGt6TNK+B+KRnUUSpXtLJfBZ+qoDc8Cg6KCP8mvFpax4jglarinVturhY5y+VGza 8xYA== X-Gm-Message-State: AC+VfDxwmW0GAO8Dvc/xknhUS8UZbAxZEDQEqz706ZNLRPc24Lx0/rlm 1K/Q39UfZ9RP4CTmSjHmVh3bhg== X-Google-Smtp-Source: ACHHUZ41/e6NYpsPmJO0DWdwanI/+UcDIguU5Jfcf7pNmuyKAPFXae54BJBHo5lO/KWa1f7rZWJCww== X-Received: by 2002:a17:906:dc92:b0:955:34a5:ae46 with SMTP id cs18-20020a170906dc9200b0095534a5ae46mr537020ejc.77.1683277771141; Fri, 05 May 2023 02:09:31 -0700 (PDT) Received: from ?IPV6:2a02:810d:15c0:828:52e:24ce:bbc1:127d? ([2a02:810d:15c0:828:52e:24ce:bbc1:127d]) by smtp.gmail.com with ESMTPSA id z16-20020a170906669000b00965b2d3968csm674500ejo.84.2023.05.05.02.09.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 05 May 2023 02:09:30 -0700 (PDT) Message-ID: <862cc092-d561-7e65-e8d4-a1c2d56a52ab@linaro.org> Date: Fri, 5 May 2023 11:09:29 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Subject: Re: [PATCH v3 2/3] spi: s3c64xx: add sleep during transfer Content-Language: en-US To: Jaewon Kim , Andi Shyti , Mark Brown , Alim Akhtar Cc: linux-spi@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Chanho Park References: <20230502062813.112434-1-jaewon02.kim@samsung.com> <20230502062813.112434-3-jaewon02.kim@samsung.com> From: Krzysztof Kozlowski In-Reply-To: <20230502062813.112434-3-jaewon02.kim@samsung.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/05/2023 08:28, Jaewon Kim wrote: > In polling mode, the status register is continuously read to check data > transfer completion. It can cause excessive CPU usage. > To reduce this, we can calculate the transfer time and put the sleep during > transfer. > > When test on ExynosAuto9 SADK board, throughput remained the same, but > 100% CPU utilization decreased to 40%. > > Signed-off-by: Jaewon Kim > --- Reviewed-by: Krzysztof Kozlowski Best regards, Krzysztof