From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758666Ab0E1PSA (ORCPT ); Fri, 28 May 2010 11:18:00 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:52030 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751748Ab0E1PR7 convert rfc822-to-8bit (ORCPT ); Fri, 28 May 2010 11:17:59 -0400 Subject: Re: [PATCH 1/2] perf: Add persistent events From: Peter Zijlstra To: Ingo Molnar Cc: Borislav Petkov , Frederic Weisbecker , Steven Rostedt , Arnaldo Carvalho de Melo , Lin Ming , linux-kernel@vger.kernel.org In-Reply-To: <20100528143311.GB9710@elte.hu> References: <1274554806-28216-1-git-send-email-bp@alien8.de> <1274554806-28216-2-git-send-email-bp@alien8.de> <1274638513.1674.1727.camel@laptop> <20100523183353.GB1408@liondog.tnic> <1274640047.1674.1731.camel@laptop> <20100523185411.GA5608@liondog.tnic> <1274642601.1674.1755.camel@laptop> <20100525073246.GA6085@liondog.tnic> <1274799588.5882.1572.camel@twins> <20100528143311.GB9710@elte.hu> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Fri, 28 May 2010 17:17:40 +0200 Message-ID: <1275059860.27810.9635.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2010-05-28 at 16:33 +0200, Ingo Molnar wrote: > > 2) get these things a buffer, perf_events as created don't actually > > have an output buffer, normally that is created at mmap() time, but > > since you cannot mmap() a kernel side event, it doesn't get to have > > a buffer. This could be done by extracting perf_mmap_data_alloc() > > into a sensible interface. > > #2 could be a new syscall: sys_create_ring_buffer or so? No, they need a buffer in-kernel, syscalls aren't the ideal tool for that :-) I've got patches refactoring the whole buffer stuff to make it more a self-contained entity.