From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755142Ab2EXJv4 (ORCPT ); Thu, 24 May 2012 05:51:56 -0400 Received: from merlin.infradead.org ([205.233.59.134]:50846 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751694Ab2EXJvz (ORCPT ); Thu, 24 May 2012 05:51:55 -0400 Subject: Re: [PATCH 02/16] perf: Add ability to attach registers dump to sample From: Peter Zijlstra To: Jiri Olsa Cc: acme@redhat.com, mingo@elte.hu, paulus@samba.org, cjashfor@linux.vnet.ibm.com, fweisbec@gmail.com, eranian@google.com, gorcunov@openvz.org, tzanussi@gmail.com, mhiramat@redhat.com, robert.richter@amd.com, fche@redhat.com, linux-kernel@vger.kernel.org, masami.hiramatsu.pt@hitachi.com, drepper@gmail.com, asharma@fb.com, benjamin.redelings@nescent.org In-Reply-To: <1337801535-12865-3-git-send-email-jolsa@redhat.com> References: <1337801535-12865-1-git-send-email-jolsa@redhat.com> <1337801535-12865-3-git-send-email-jolsa@redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 24 May 2012 11:51:50 +0200 Message-ID: <1337853110.9783.93.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-05-23 at 21:32 +0200, Jiri Olsa wrote: > +perf_output_sample_regs(struct perf_output_handle *handle, > + struct pt_regs *regs, u64 mask) > +{ > + int i = 0; > + > + do { > + u64 val; > + > + if (mask & 1) { > + val = perf_reg_value(regs, i); > + perf_output_put(handle, val); > + } > + > + mask >>= 1; > + i++; > + } while (mask); > +} we have bitmap functions available that can do this far faster on a number of architectures (like x86) that have bit scanning instructions.