From patchwork Thu Feb 17 03:48:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Cromie X-Patchwork-Id: 12749308 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9B092C433FE for ; Thu, 17 Feb 2022 03:49:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6883110E826; Thu, 17 Feb 2022 03:49:03 +0000 (UTC) Received: from mail-io1-xd30.google.com (mail-io1-xd30.google.com [IPv6:2607:f8b0:4864:20::d30]) by gabe.freedesktop.org (Postfix) with ESMTPS id A397B10E7BC; Thu, 17 Feb 2022 03:48:53 +0000 (UTC) Received: by mail-io1-xd30.google.com with SMTP id i74so211335ioa.0; Wed, 16 Feb 2022 19:48:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=14+i519RyXRhGHkk7y/NizorIrgQMa72y8v5Vs7LOmo=; b=oHx5SA+pA20pWvzGLkJ4yhng4E+IvjuoVEMElPdEpgwBAXZX8Ayc2SvfCLXwvFcehP o0AHme5wuSQ63YxgN3QSc0rUbOV/j/+6G6zQRS4NCVt/yEL1Crq/uwf9UDEKebgjg//9 QjwYPtTiQ0qXnz1UoGaup0sTfsdK8RdEHeUiQduq7H62ZAi7uIXJLbm6AdTtwuFcGXuD HV1h9OqMqWbRjdNwm8pC+0EWihoDDr44lxgfi0RIrrwF4+9Cz21iiE95YFoJBmglrB4c uqhiYzFY7DXRbPHXJsC8Kzs9wY0qwRswwrK0gBC7Y2uHlx1hH59CcbFMZGDMbalV1nve ffkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=14+i519RyXRhGHkk7y/NizorIrgQMa72y8v5Vs7LOmo=; b=1877tvCGV/fffkOCYpgCPy/FjZJq/JFct6RZDhon4A7R8LqmOkBD1BAnRNQuyQ7TgB xXjPIw8RINLcjybF7N84f/H+3KfAa5PqSw82tDVUtXLjNJLA6uwXeSJCKrEHdkXMGphb nlhI6LIt7WTLdg6VrEJhZueJzpgqmLVlbj9i8Pyz6pJqhDohhQZvx3C6g6GI4RycSCBU WsrznVKuIajtTHzOXDy/h9AYVg2A8UdZQs/d+oJELKOEj30/rnu9MsRNwLOr3KqnAiJb MkSJSGhvXjkgngJ61G7l6rbOHmo47mX5bRUR96dHofyEPZ5JbZvpsgRFAA4MovFYvhJi 0BYQ== X-Gm-Message-State: AOAM533gy0cI0ykC4YM81ob4UkObCrif4Em2jlF/TLKAgBwsNH+UtaOr kA9uh/qjrm2KFbH2gK+tVV0= X-Google-Smtp-Source: ABdhPJwQdM+YASo9bZwGxmAll7Ye37UoRGfnFLBMbW70/Q8CqJm3xpdtwTbFefjn4OZb9vDTlUFoSw== X-Received: by 2002:a05:6638:1350:b0:314:7f2a:ab14 with SMTP id u16-20020a056638135000b003147f2aab14mr717303jad.215.1645069731093; Wed, 16 Feb 2022 19:48:51 -0800 (PST) Received: from frodo.hsd1.co.comcast.net ([2601:284:8204:2010::1b19]) by smtp.googlemail.com with ESMTPSA id l16sm1127874ilc.54.2022.02.16.19.48.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Feb 2022 19:48:50 -0800 (PST) From: Jim Cromie To: jbaron@akamai.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Date: Wed, 16 Feb 2022 20:48:26 -0700 Message-Id: <20220217034829.64395-11-jim.cromie@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220217034829.64395-1-jim.cromie@gmail.com> References: <20220217034829.64395-1-jim.cromie@gmail.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 10/13] drm_print: refine drm_debug_enabled for dyndbg+jump-label X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jim Cromie , daniel.vetter@ffwll.ch, linux@rasmusvillemoes.dk, seanpaul@chromium.org, joe@perches.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" In order to use dynamic-debug's jump-label optimization in drm-debug, its clarifying to refine drm_debug_enabled into 3 uses: 1. drm_debug_enabled - legacy, public 2. __drm_debug_enabled - optimized for dyndbg jump-label enablement. 3. _drm_debug_enabled - pr_debug instrumented, observable 1. The legacy version always checks the bits. 2. is privileged, for use by __drm_dbg(), __drm_dev_dbg(), which do an early return unless the category is enabled (free of call/NOOP side effects). For dyndbg builds, debug callsites are selectively "pre-enabled", so __drm_debug_enabled() short-circuits to true there. Remaining callers of 1 may be able to use 2, case by case. 3. is 1st wrapped in a macro, with a pr_debug, which reports each usage in /proc/dynamic_debug/control, making it observable in the logs. The macro lets the pr_debug see the real caller, not an inline function. When plugged into 1, it identified ~10 remaining callers of the function, leading to the follow-on cleanup patch, and would allow activating the pr_debugs, estimating the callrate, and the potential savings by using the wrapper macro. It is unused ATM, but it fills out the picture. Signed-off-by: Jim Cromie --- drivers/gpu/drm/drm_print.c | 4 ++-- include/drm/drm_print.h | 28 ++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index e45ba224e57c..92e6e18026da 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -262,7 +262,7 @@ void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category, struct va_format vaf; va_list args; - if (!drm_debug_enabled(category)) + if (!__drm_debug_enabled(category)) return; va_start(args, format); @@ -285,7 +285,7 @@ void ___drm_dbg(enum drm_debug_category category, const char *format, ...) struct va_format vaf; va_list args; - if (!drm_debug_enabled(category)) + if (!__drm_debug_enabled(category)) return; va_start(args, format); diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index 06f0ee06be1f..38ef044d786e 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -319,11 +319,39 @@ enum drm_debug_category { DRM_UT_DRMRES }; +/* + * 3 name flavors of drm_debug_enabled: + * drm_debug_enabled - public/legacy, always checks bits + * _drm_debug_enabled - instrumented to observe call-rates, est overheads. + * __drm_debug_enabled - privileged - knows jump-label state, can short-circuit + */ static inline bool drm_debug_enabled(enum drm_debug_category category) { return unlikely(__drm_debug & BIT(category)); } +/* + * Wrap fn in macro, so that the pr_debug sees the actual caller, not + * the inline fn. Using this name creates a callsite entry / control + * point in /proc/dynamic_debug/control. + */ +#define _drm_debug_enabled(category) \ + ({ \ + pr_debug("todo: maybe avoid via dyndbg\n"); \ + drm_debug_enabled(category); \ + }) + +#if defined(CONFIG_DRM_USE_DYNAMIC_DEBUG) +/* + * dyndbg is wrapping the drm.debug API, so as to avoid the runtime + * bit-test overheads of drm_debug_enabled() in those api calls. + * In this case, executed callsites are known enabled, so true. + */ +#define __drm_debug_enabled(category) true +#else +#define __drm_debug_enabled(category) drm_debug_enabled(category) +#endif + /* * struct device based logging *