From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752214AbaBQQII (ORCPT ); Mon, 17 Feb 2014 11:08:08 -0500 Received: from mga02.intel.com ([134.134.136.20]:61711 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751005AbaBQQIG (ORCPT ); Mon, 17 Feb 2014 11:08:06 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.95,861,1384329600"; d="scan'208";a="476575555" Date: Mon, 17 Feb 2014 08:07:34 -0800 From: Andi Kleen To: Peter Zijlstra Cc: Alexander Shishkin , Ingo Molnar , linux-kernel@vger.kernel.org, Frederic Weisbecker , Mike Galbraith , Paul Mackerras , Stephane Eranian , Adrian Hunter , Matt Fleming Subject: Re: [PATCH v1 07/11] x86: perf: intel_pt: Intel PT PMU driver Message-ID: <20140217160734.GU12219@tassilo.jf.intel.com> References: <1391683834-29868-1-git-send-email-alexander.shishkin@linux.intel.com> <1391683834-29868-8-git-send-email-alexander.shishkin@linux.intel.com> <20140217144436.GS27965@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140217144436.GS27965@twins.programming.kicks-ass.net> 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 > So MAX_ORDER is 11, which gives us (11+12) 23bit or 8M max allocations, right? > > Given this TOPA stuff is completely fucked in the first release, that's > about all we can get it, right? > > Now given you said 100s MB/s data rate for this itrace stuff, we're at > ~0.1s traces. And that's in the very best case where we can actually get > 8M. > > Is that a workable amount The PMI handler switches to a new buffer to allow longer traces in memory. It just costs one PMI. -Andi -- ak@linux.intel.com -- Speaking for myself only