From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: what is the default frequency and default event period set in "perf record -TP" Date: Wed, 06 Nov 2013 17:38:32 -0700 Message-ID: <527AE108.6020905@gmail.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-pb0-f54.google.com ([209.85.160.54]:46059 "EHLO mail-pb0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751772Ab3KGAif (ORCPT ); Wed, 6 Nov 2013 19:38:35 -0500 Received: by mail-pb0-f54.google.com with SMTP id ro12so277314pbb.27 for ; Wed, 06 Nov 2013 16:38:35 -0800 (PST) In-Reply-To: Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Peipei Wang , perf group On 11/6/13, 4:52 PM, Peipei Wang wrote: > Hi all/David, > > I want to know the frequency in the following command: > perf record -e cycles -e cache-misses -e cache-references -TP > -o abc.data command > > I looked up in the perfwiki, and it says the default value is 1000. > However, when I specify this parameter in the above command,that is, > "perf record -e cycles -e cache-misses -e cache-references -TP -F 1000 > -o abc.data command", I found a significant difference between the > file data size. > > Using the first command, the size of "abc.data" is about 500MB, but > the second command could generate the raw data size up to over 10GB. > > > I could not figure out the reason. Is it might because sampling mode > of cycles is based on frequency while the other two events are based > on event period? default frequency was bumped to 4000 about a year ago. Not sure how the -F is impacting the cache-xxxx events. David