Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754773AbZI3RGb (ORCPT ); Wed, 30 Sep 2009 13:06:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754651AbZI3RGa (ORCPT ); Wed, 30 Sep 2009 13:06:30 -0400 Received: from sj-iport-1.cisco.com ([171.71.176.70]:59357 "EHLO sj-iport-1.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754447AbZI3RG3 (ORCPT ); Wed, 30 Sep 2009 13:06:29 -0400 Authentication-Results: sj-iport-1.cisco.com; dkim=pass (signature verified [TEST]) header.i=rdreier@cisco.com X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApoEAE8tw0qrR7PE/2dsb2JhbADBFYhbAZAMBoQngjI X-IronPort-AV: E=Sophos;i="4.44,481,1249257600"; d="scan'208";a="249166808" From: Roland Dreier To: Ingo Molnar Cc: Pavel Machek , Peter Zijlstra , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, Paul Mackerras , Anton Blanchard , general@lists.openfabrics.org, akpm@linux-foundation.org, torvalds@linux-foundation.org Subject: Re: [ofa-general] Re: [GIT PULL] please pull ummunotify References: <1253187028.8439.2.camel@twins> <1253198976.14935.27.camel@laptop> <20090929171332.GD14405@elf.ucw.cz> <20090930094456.GD24621@elte.hu> X-Message-Flag: Warning: May contain useful information Date: Wed, 30 Sep 2009 10:06:32 -0700 In-Reply-To: <20090930094456.GD24621@elte.hu> (Ingo Molnar's message of "Wed, 30 Sep 2009 11:44:56 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.91 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 30 Sep 2009 17:06:32.0692 (UTC) FILETIME=[5C1E3340:01CA41F0] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1494 Lines: 35 > Performance events filtering is being worked on and now with the proper > non-DoS limit you've added you can lose events too, dont you? So it's > all a question of how much buffering to add - and with perf events too > you can buffer arbitrary large amount of events. No, the idea for non-DoS for ummunotify is that we would limit the number of regions the application can register; so an application might hit the limit up front but no runtime loss of events once a region was registered successfully. > I think this could be done in a simpler, less limited, more generic, > more useful form by using some variation of perf events. > > You should be able to get all that you want by adding two TRACE_EVENT() > tracepoints and using the existing perf event syscall to get the events > to user-space. Yes, I would like to use perf events too. Would it be plausible to create a way for userspace to create a "counter" for each address range being watched? Then events would not be lost, because those counters would become non-zero. > Meaning that this: > 9 files changed, 1060 insertions(+), 1 deletions(-) Note that lots/ of the files touched here are in Documentation or are one-line changes to Makefiles etc. - R. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/