From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753154AbaBJR7A (ORCPT ); Mon, 10 Feb 2014 12:59:00 -0500 Received: from merlin.infradead.org ([205.233.59.134]:55767 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752312AbaBJR67 (ORCPT ); Mon, 10 Feb 2014 12:58:59 -0500 Date: Mon, 10 Feb 2014 18:58:54 +0100 From: Peter Zijlstra To: Mark Rutland Cc: linux-kernel@vger.kernel.org, will.deacon@arm.com, dave.martin@arm.com, Ingo Molnar Subject: Re: [PATCH 4/7] perf: be less pessimistic when scheduling events Message-ID: <20140210175854.GB27965@twins.programming.kicks-ass.net> References: <1392054264-23570-1-git-send-email-mark.rutland@arm.com> <1392054264-23570-5-git-send-email-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1392054264-23570-5-git-send-email-mark.rutland@arm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 10, 2014 at 05:44:21PM +0000, Mark Rutland wrote: > This patch makes ctx_flexible_sched_in attempt to schedule every group > in the flexible_groups list even when earlier groups failed to schedule, > enabling more groups to be scheduled simultaneously. Since you're basically free to create as many events as you want, you can (as an unprivilidged user) make the context switch to and from your task arbitrarily expensive. So no, that's not going to fly.