From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932106AbbB0Unz (ORCPT ); Fri, 27 Feb 2015 15:43:55 -0500 Received: from mail.kernel.org ([198.145.29.136]:33210 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753016AbbB0Uny (ORCPT ); Fri, 27 Feb 2015 15:43:54 -0500 Date: Fri, 27 Feb 2015 17:43:46 -0300 From: Arnaldo Carvalho de Melo To: Pavel Odintsov Cc: linux-kernel@vger.kernel.org, David Ahern Subject: Re: [PATCH 0/7] [RFC] kernel: add a netlink interface to get information about processes Message-ID: <20150227204346.GB28401@kernel.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Thu, Feb 19, 2015 at 05:00:12PM +0400, Pavel Odintsov escreveu: > Hello! > > In addition to my post I want to mention another issue related with > slow /proc read in perf toolkit. On my server with 25 000 processes I > need about ~15 minutes for loading perf top toolkit completely. > > https://bugzilla.kernel.org/show_bug.cgi?id=86991 Right, one way would be to, in the 'perf top' case to defer getting thread information to when we need it, i.e. when we get a sample for a pid that we have no struct thread associated with. We would speed up 'perf top' startup but would introduce jitter down the line, and would be up for races, but hey, we already are, using /proc :-/ But that would not work for 'perf record', as we need to in advance generate those records as we don't do any processing of samples... Yeah, for preexisting threads we do have a problem since day one, what we use is just what can be done with existing stuff. I saw that there were some more messages in this thread, its just that I haven't found them in my mailbox when David Ahern pointed this out this discussion to me :-\ >>From the subject line, there is patchkit, but I couldn't find it... Can you resend it to me or point me to some url where I can get it? - Arnaldo