From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752242AbaEGTBT (ORCPT ); Wed, 7 May 2014 15:01:19 -0400 Received: from mail-ee0-f41.google.com ([74.125.83.41]:57917 "EHLO mail-ee0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750996AbaEGTBR (ORCPT ); Wed, 7 May 2014 15:01:17 -0400 Date: Wed, 7 May 2014 21:01:11 +0200 From: Ingo Molnar To: Jiri Olsa Cc: Namhyung Kim , linux-kernel@vger.kernel.org, Corey Ashford , David Ahern , Frederic Weisbecker , Paul Mackerras , Peter Zijlstra , Arnaldo Carvalho de Melo , Jean Pihet Subject: Re: [PATCH 2/3] perf tools: Cache dso data file descriptor Message-ID: <20140507190111.GA21160@gmail.com> References: <1397756352-26694-1-git-send-email-jolsa@redhat.com> <1397756352-26694-3-git-send-email-jolsa@redhat.com> <1398609395.1689.17.camel@leonhard> <20140428100133.GE1109@krava.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20140428100133.GE1109@krava.brq.redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jiri Olsa wrote: > On Sun, Apr 27, 2014 at 11:36:35PM +0900, Namhyung Kim wrote: > > 2014-04-17 (목), 19:39 +0200, Jiri Olsa: > > > Keeping the data file description open for the whole life > > > of the dso object. > > > > I suspect there might be an issue for reporting very large data file > > with this approach - like open file limit? > > I've got as high as ~200 openned file descriptors for > ~2GB data of system wide monitoring Note that 200 open file descriptors in themselves are not a scalability problem on Linux, as long as perf doesn't walk them linearly anywhere. I think we are reasonably fast even with a million open files in a singe process, or so. Thanks, Ingo