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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 F3A5CC352AA for ; Tue, 1 Oct 2019 16:35:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C31062168B for ; Tue, 1 Oct 2019 16:35:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="ddoHkIS2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731102AbfJAQfp (ORCPT ); Tue, 1 Oct 2019 12:35:45 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:46967 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726063AbfJAQfp (ORCPT ); Tue, 1 Oct 2019 12:35:45 -0400 Received: by mail-pf1-f193.google.com with SMTP id q5so8364687pfg.13 for ; Tue, 01 Oct 2019 09:35:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=atMkE3+ksZjOVD8COwMqPXYfvUwFAn8HGygWZmnodkw=; b=ddoHkIS2jNwy/leh8M6Pn55XjIVeRT7kNE2CgSfYK6DSixUkq4bdQSVEGIcnY1ua/c 0atFBkR3Zfdo0KNu4LUiZAksyy7OtsN2gGLh12BSbhfl7TeVX4HnyKowU+95+gpj8VsS G5EDsbokGIjGKpCp9FGnrFm5A6BSBYfXVOKQ0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=atMkE3+ksZjOVD8COwMqPXYfvUwFAn8HGygWZmnodkw=; b=SS9bNUM+4zIdpSRKF1q2sRpMiWKgrQZeGSJOXb4BIPvv9Ea/uR/NoeB60iBXyMJ8kO fhOMC5li4xDuHhYMhBZPkQSCUOBsS7h23+Z/3Ag5apKjy1jbF9IC7DiJ+jTwxmx5FmMT pGyTJUuiDN0TJp6+b9lEC+QAVaVGApfpJ+uZIlfmXN+FzsXG5X6kLCJ8qAoEo5iKKyjm 9icbHtjAzivCUyZzc6P+NTROdyG9mmaqNB3g7sRkiMhvBCwtkgaH7ad5DE4CktNFkLdQ /GS6zNii/+wmes0cRbp4PPL9dIwHY5ChtvJLw5T20+8vDg5OnZOaliq+mXpqDaHYZK4H KYNA== X-Gm-Message-State: APjAAAWDrgX1ET0l3utJeQ7poRGSy5c18QlBMwr145F9eCWfreTJwDWN X+3XFINl46+vFmeAhHH08DQaKg== X-Google-Smtp-Source: APXvYqwZAmTy3spFW3KEZLKtOByAgOvBEuREAByP0PaoogzwFCJAY2pIj4bQ2yeV4p/lLCpUqSm8rw== X-Received: by 2002:a62:e814:: with SMTP id c20mr29298154pfi.209.1569947744868; Tue, 01 Oct 2019 09:35:44 -0700 (PDT) Received: from localhost ([2620:15c:202:1:4fff:7a6b:a335:8fde]) by smtp.gmail.com with ESMTPSA id q13sm5814074pjq.0.2019.10.01.09.35.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 01 Oct 2019 09:35:44 -0700 (PDT) Date: Tue, 1 Oct 2019 09:35:42 -0700 From: Matthias Kaehlcke To: Steven Rostedt Cc: "Rafael J . Wysocki" , Kevin Hilman , Ulf Hansson , Len Brown , Pavel Machek , Greg Kroah-Hartman , Ingo Molnar , Douglas Anderson , linux-pm@vger.kernel.org, Amit Kucheria , linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] PM / Domains: Add tracepoints Message-ID: <20191001163542.GB87296@google.com> References: <20190926150406.v1.1.I07a769ad7b00376777c9815fb169322cde7b9171@changeid> <20190927044239.589e7c4c@oasis.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190927044239.589e7c4c@oasis.local.home> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 27, 2019 at 04:42:39AM -0400, Steven Rostedt wrote: > On Thu, 26 Sep 2019 15:04:38 -0700 > Matthias Kaehlcke wrote: > > > Define genpd_power_on/off and genpd_set_performance_state > > tracepoints and use them. > > I agree with Greg about adding a "why" you need this. But, in case > there's a good reason to have this, I have comments about the code > below. Thanks Greg and Steven for your comments. How about this instead: Add tracepoints for genpd_power_on, genpd_power_off and genpd_set_performance_state. The tracepoints can help with understanding power domain behavior of a given device, which may be particularly interesting for battery powered devices and suspend/resume. > > Signed-off-by: Matthias Kaehlcke > > --- > > > > drivers/base/power/domain.c | 27 +++++++++++++++++--- > > include/trace/events/power.h | 49 ++++++++++++++++++++++++++++++++++++ > > 2 files changed, 72 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c > > index cc85e87eaf05..aee988c112e5 100644 > > --- a/drivers/base/power/domain.c > > +++ b/drivers/base/power/domain.c > > @@ -21,6 +21,7 @@ > > #include > > #include > > #include > > +#include > > > > #include "power.h" > > > > @@ -329,6 +330,9 @@ static int _genpd_set_performance_state(struct generic_pm_domain *genpd, > > goto err; > > > > genpd->performance_state = state; > > + > > + trace_genpd_set_performance_state(genpd); > > + > > return 0; > > > > err: > > @@ -418,14 +422,21 @@ static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed) > > if (!genpd->power_on) > > return 0; > > > > - if (!timed) > > - return genpd->power_on(genpd); > > + if (!timed) { > > + ret = genpd->power_on(genpd); > > + if (!ret) > > + trace_genpd_power_on(genpd); > > + > > + return ret; > > + } > > > > time_start = ktime_get(); > > ret = genpd->power_on(genpd); > > if (ret) > > return ret; > > > > + trace_genpd_power_on(genpd); > > + > > elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start)); > > if (elapsed_ns <= genpd->states[state_idx].power_on_latency_ns) > > return ret; > > @@ -448,14 +459,22 @@ static int _genpd_power_off(struct generic_pm_domain *genpd, bool timed) > > if (!genpd->power_off) > > return 0; > > > > - if (!timed) > > - return genpd->power_off(genpd); > > + if (!timed) { > > + ret = genpd->power_off(genpd); > > + if (!ret) > > Here > > > + trace_genpd_power_off(genpd); > > + > > + return ret; > > + } > > > > time_start = ktime_get(); > > ret = genpd->power_off(genpd); > > if (ret) > > return ret; > > > > + if (!ret) > > And here add a conditional branch for only a tracepoint. To eliminate > the branch when tracepoints are not enabled, please do it this way > instead: > > if (trace_genpd_power_off_enabled() && !ret) > > The above is a static branch (nop when disabled, and jmp when enabled), > and the above should move the conditional branch on !ret into the > section that is only called when the tracepoint is enabled. ok, will do in future versions.