From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cody P Schafer Subject: Re: What does the "scaled from 66.58%" means?? What is scaled?? Date: Mon, 24 Jun 2013 16:36:06 -0700 Message-ID: <51C8D7E6.2040401@codyps.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ie0-f182.google.com ([209.85.223.182]:56322 "EHLO mail-ie0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750820Ab3FXXgo (ORCPT ); Mon, 24 Jun 2013 19:36:44 -0400 Received: by mail-ie0-f182.google.com with SMTP id s9so26579829iec.27 for ; Mon, 24 Jun 2013 16:36:44 -0700 (PDT) In-Reply-To: Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Peipei Wang Cc: perf group On 06/24/2013 03:37 PM, Peipei Wang wrote: > perf stat -B dd if=/dev/zero of=/dev/null count=1000000 > > 1000000+0 records in > 1000000+0 records out > 512000000 bytes (512 MB) copied, 0.956217 s, 535 MB/s > > Performance counter stats for 'dd if=/dev/zero of=/dev/null count=1000000': > > 5,099 cache-misses # 0.005 M/sec (scaled > from 66.58%) > 235,384 cache-references # 0.246 M/sec (scaled > from 66.56%) > 9,281,660 branch-misses # 3.858 % (scaled > from 33.50%) > 240,609,766 branches # 251.559 M/sec (scaled > from 33.66%) > 1,403,561,257 instructions # 0.679 IPC (scaled > from 50.23%) > 2,066,201,729 cycles # 2160.227 M/sec (scaled > from 66.67%) > ... > Can anyone explain to me the meaning of "scaled from", and from which > get the 66.58% or 33.50%?? The scaling indicates that we had to time slice performance events because we couldn't enable them all at once. The 33% indicates that that event was only active 33% of the time, so we've scaled it (multiplied by 3, in this case) with the assumption that it would show up with the same frequency during the times it was disabled. (Same for 66%).