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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 81998C76190 for ; Mon, 22 Jul 2019 19:46:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56CF8216F4 for ; Mon, 22 Jul 2019 19:46:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="GOl+n50o"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="ERr2t9Tz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729797AbfGVTq1 (ORCPT ); Mon, 22 Jul 2019 15:46:27 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:39782 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728728AbfGVTq1 (ORCPT ); Mon, 22 Jul 2019 15:46:27 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id F15B960F3E; Mon, 22 Jul 2019 19:46:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1563824786; bh=7eD+eVqFrtz3xwFVMMyatV/ixJ3r8Kbtxeq9wzu5IKQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GOl+n50oNJeKGpt1Z0Psg6IsQpupO2+uH9JxXDplcwwpU+dSKAJAmcg+8J3jGxpq5 qf1rHJQ3vBKSAIu45h5jk6LpUa070gZ6UF7xRH/U5v8uOjyfiZztRuGZmf5BH5NS3Z DhVuipozaH1XgVVBX02F7knbBYhbfRQuML0OyNOs= Received: from localhost (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: ilina@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 1808460E72; Mon, 22 Jul 2019 19:46:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1563824785; bh=7eD+eVqFrtz3xwFVMMyatV/ixJ3r8Kbtxeq9wzu5IKQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ERr2t9TzgA7dmFYQp6vEONA9i9/l5p8TslDfJQXB+JVAmLHefAc6cSxX7TYP2fcJD +URQ4J+SrDUSabnJqEPXVI0x90iUETo84prVGXQIJYcVbXNO/6qe1IUaxJGpEMYxV8 uxKnXuhGMVwRqMziIXCugnf7xhWEK0byf4+wjnTs= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 1808460E72 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=ilina@codeaurora.org Date: Mon, 22 Jul 2019 13:46:24 -0600 From: Lina Iyer To: Stephen Boyd Cc: andy.gross@linaro.org, bjorn.andersson@linaro.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, rnayak@codeaurora.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, dianders@chromium.org, mkshah@codeaurora.org, "Raju P.L.S.S.S.N" Subject: Re: [PATCH 1/2] drivers: qcom: rpmh-rsc: simplify TCS locking Message-ID: <20190722194624.GA11589@codeaurora.org> References: <20190701152907.16407-1-ilina@codeaurora.org> <5d3209e7.1c69fb81.5ef1.5195@mx.google.com> <20190722162003.GG25567@codeaurora.org> <5d35fdfb.1c69fb81.5fafa.aaa9@mx.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <5d35fdfb.1c69fb81.5fafa.aaa9@mx.google.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Mon, Jul 22 2019 at 12:18 -0600, Stephen Boyd wrote: >Quoting Lina Iyer (2019-07-22 09:20:03) >> On Fri, Jul 19 2019 at 12:20 -0600, Stephen Boyd wrote: >> >Quoting Lina Iyer (2019-07-01 08:29:06) >> >> From: "Raju P.L.S.S.S.N" >> >> >> >> tcs->lock was introduced to serialize access with in TCS group. But >> >> even without tcs->lock, drv->lock is serving the same purpose. So >> >> use a single drv->lock. >> > >> >Isn't the downside now that we're going to be serializing access to the >> >different TCSes when two are being written in parallel or waited on? I >> >thought that was the whole point of splitting the lock into a TCS lock >> >and a general "driver" lock that protects the global driver state vs. >> >the specific TCS state. >> > >> Yes but we were holding the drv->lock as well as tcs->lock for the most >> critical of the path anyways (writing to TCS). The added complexity >> doesn't seem to help reduce the latency that it expected to reduce. > >Ok. That sort of information should be in the commit text to explain why >it's not helping with reducing the latency or throughput of the API. > Will add. --Lina