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=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 CDE69C432C3 for ; Wed, 13 Nov 2019 16:33:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4B7C204EA for ; Wed, 13 Nov 2019 16:33:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=generalsoftwareinc-com.20150623.gappssmtp.com header.i=@generalsoftwareinc-com.20150623.gappssmtp.com header.b="XaiDIDDt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728434AbfKMQda (ORCPT ); Wed, 13 Nov 2019 11:33:30 -0500 Received: from mail-vs1-f68.google.com ([209.85.217.68]:41553 "EHLO mail-vs1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726521AbfKMQda (ORCPT ); Wed, 13 Nov 2019 11:33:30 -0500 Received: by mail-vs1-f68.google.com with SMTP id 190so1745306vss.8 for ; Wed, 13 Nov 2019 08:33:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=generalsoftwareinc-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=EMqO7kO+eGq0uCIQ1EQILqtM2ejcR6sdBUV13AtA/lk=; b=XaiDIDDtPVY40xuVO13Q/1v0UVMXCUMTz9cC7XOMCVRm1GcuhOAK9WCwAL0vdpJ3Il Jlw/rEZS2aFPaNetjY5RElc/Mfud2PtkVURTTzhq7z/Tzg6IzVx21Wt7xJVyVnQVbjjD eF1uGxtrs0jFLbYHX168KizsPTdPhvycgGSrjeTG9H2af0NI0nIyP43tgzsydTeXJQOD TnV59ZoVoN/zBwyBIIe+sPskrI9l++l7yvE+nYVsXaoKbvRW/Td7bPyEAiTMRuTxafzc edDMQG/94ozk80m58lfWGYU88wihBWMDGk5ZLYOB1Ch7F/wAND0IAjHvQ0zkTTjT7rcq 6iHw== 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=EMqO7kO+eGq0uCIQ1EQILqtM2ejcR6sdBUV13AtA/lk=; b=RTL9mQ2yQ3fCVHR061IkNJA8BsRv5mVljXJW2rcTrDAukF+1TPLP4Ku+MFQ6aH80Jg jlYe0RzXUu2KuOGjKFEtiuRRuWB1k0l0I6tTdOxd5YHms86OB8gic8+oPFYBuQGD2R+i PSP06fQjROXW3VUokeRn4OWHAU0d8XFNxIEhj+a+1GFDAxka+Po5ulN0v2N5pmGPo9wr I4MLzbR/qJfV3QdTMJlV3wClL4HUEu1+vbgCdXwEqMKjf4VRoezcdoTghJDTW6Cp/40N LjEVIo1Osqz6XXO+oviBrLqqRWFKX0eY0Em+D4R1gIbYRwRa+O5SWeiHUpC0xORpHgwD Kyxg== X-Gm-Message-State: APjAAAXu0nd3VblHrhTJizDCTQrUa4Bxybd4qRzqyJXXvR6VcehZhzw2 jvjcWAkIugVteZ1N0EmMU/JPCw== X-Google-Smtp-Source: APXvYqzI2uGfY1AjLJBGPLMwVGPxmNpIdIDSf0dVimu/BkUp0yx8RWSj5ex9NX6esogZOPKMKUVuzQ== X-Received: by 2002:a05:6102:7ce:: with SMTP id y14mr2401899vsg.220.1573662808770; Wed, 13 Nov 2019 08:33:28 -0800 (PST) Received: from ubuntu1804-desktop ([172.97.41.74]) by smtp.gmail.com with ESMTPSA id b26sm612034uaf.5.2019.11.13.08.33.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 Nov 2019 08:33:28 -0800 (PST) Date: Wed, 13 Nov 2019 11:33:27 -0500 From: "Frank A. Cancio Bello" To: Steven Rostedt , Ingo Molnar , Jonathan Corbet , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Cc: joel@joelfernandes.org, saiprakash.ranjan@codeaurora.org Subject: [RFC 2/2] ** do not apply this patch ** Just for illustration purposes Message-ID: <141cb10cc2eabc5c3130496f12d84dd1ef247e20.1573661658.git.frank@generalsoftwareinc.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Prints a message that will allow us to evaluate the number of pages allocated by each CPU buffer as well the main values that participate in its calculation. $ echo 0 > /sys/kernel/debug/tracing/tracing_on $ echo 4096 > /sys/kernel/debug/tracing/buffer_size_kb .... e.g. of output: PAGE_SIZE: 4096, BUF_PAGE_HDR_SIZE: 16, size: 4194304, nr_pages: 1029 Signed-off-by: Frank A. Cancio Bello --- kernel/trace/ring_buffer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 66358d66c933..c10b6bcb29b9 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1730,6 +1730,8 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, return size; nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE); + printk(KERN_ALERT "PAGE_SIZE: %lu, BUF_PAGE_HDR_SIZE: %lu, size: %lu, nr_pages: %ld", + PAGE_SIZE, BUF_PAGE_HDR_SIZE, size, nr_pages); /* we need a minimum of two pages */ if (nr_pages < 2) -- 2.17.1