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=-13.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_NONE,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 AC7E2C11F66 for ; Wed, 30 Jun 2021 22:35:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C0436100B for ; Wed, 30 Jun 2021 22:35:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234112AbhF3Wh1 (ORCPT ); Wed, 30 Jun 2021 18:37:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234165AbhF3Wgy (ORCPT ); Wed, 30 Jun 2021 18:36:54 -0400 Received: from mail-qt1-x831.google.com (mail-qt1-x831.google.com [IPv6:2607:f8b0:4864:20::831]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE7E0C0617AD for ; Wed, 30 Jun 2021 15:34:23 -0700 (PDT) Received: by mail-qt1-x831.google.com with SMTP id r20so2761753qtp.3 for ; Wed, 30 Jun 2021 15:34:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=oDBeFzOeSYMajUq4z+RXiKNq7rQAt1gBDq5Z6Cf+y/c=; b=eY7qay9OFBKD9WyfWcDfvsAExyXjD6G8Z7MCYiObz3P66eVyVXJDuYc4I4H7YBjv1G LOrUtyvR8gPD1V2BpTy+08a+Ws64UX1vkAYLpZLd18850iBLxI0L8S9SuvhqrNGW6P3M 9XVRxoWLFj5l8WNxyarmxWFjieIpR/TkCxru8yAtgRTaeoz5Y81AN4OFx7Ttxg5zTudc hUzlfOSJmXGRmArpkrAuCpKCxEIIG0JjfcthhTAgXLvqT8+KdmL9PaRPTbPp3bPDRI4t czh1HsjsMrBNSQOqIFZbI0PlWCfRGLkcVX6DA3NFzy+SU5QHWZh8RnfvGULN8JDfDYuC ATDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=oDBeFzOeSYMajUq4z+RXiKNq7rQAt1gBDq5Z6Cf+y/c=; b=Oc/t352ATsobgZH0PT6uzN0DGnwIlctbUagN9qmetdHA6/BSXnm5SfNUfQjbJSTOOK 05JcXua+lP1LT8bB0RVbESKlRDu8D6hbJ/xF6zvaXNSx4aSEp4F90+YGqueRuJ5MCgPm ldq3xmek1fGN/UDCvx5z/weh7GfKhkrrLjJwMDCauMfpyyz4NqZgRsOTNp9qL+bKrcp5 7K2ECZgw/tK1xFK6Oui24QbCEPM7sm3dqrDuTWzgcT6V/voS3PV7d8pQAxPGiPdqyNNQ cweRGhd/D43uU4SQ/srleYSTThYiO2J/KNq3zffAtNysDMmJSWYSzivzrCfoyrOWu0xH 5e2Q== X-Gm-Message-State: AOAM531VWmhBxi6Eowhd9MlGWi7JksIjzvC8jsuLLW2//drcjlieBou5 GhcTJ7lRWs9yF1UEDtqScQEZ2O/JoIzpiLNYak4RVw== X-Google-Smtp-Source: ABdhPJwrSvGWPQao8zHcABCMuiXxI/BRQPB4DIe7y60UDvcfYfGul0J9WFL1LSjY4Je8Ohgl7IefoZENhmAxer+HXXc= X-Received: by 2002:ac8:604:: with SMTP id d4mr33769426qth.304.1625092462907; Wed, 30 Jun 2021 15:34:22 -0700 (PDT) MIME-Version: 1.0 References: <20210630003406.4013668-1-paulburton@google.com> <20210630003406.4013668-2-paulburton@google.com> <20210630083513.1658a6fb@oasis.local.home> <20210630173400.7963f619@oasis.local.home> In-Reply-To: <20210630173400.7963f619@oasis.local.home> From: Joel Fernandes Date: Wed, 30 Jun 2021 18:34:11 -0400 Message-ID: Subject: Re: [PATCH 2/2] tracing: Resize tgid_map to PID_MAX_LIMIT, not PID_MAX_DEFAULT To: Steven Rostedt Cc: Paul Burton , linux-kernel@vger.kernel.org, Ingo Molnar , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 30, 2021 at 5:34 PM Steven Rostedt wrote: [..] > > Having said that I think taking a similar approach to saved_cmdlines > > would be better than what we have now, though I'm not sure whether it'll > > be sufficient to actually be usable for me. My use case is grouping > > threads into processes when displaying scheduling information, and > > experience tells me that if any threads don't get grouped appropriately > > the result will be questions. > > I found a few bugs recently in the saved_cmdlines that were causing a > much higher miss rate, but now it's been rather accurate. I wonder how > much pain that's been causing you? > > Anyway, I'll wait to hear what Joel says on this. If he thinks this is > worth 16M of memory when enabled, I may take it. I am not a huge fan of the 16M, in Android we enable this feature on all devices. Low end Android devices traced in the field are sometimes 1 GB and the added memory pressure may be unwelcome. Very least, maybe make it optional only for folks who increase pid_max? thanks, -Joel