From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-qy0-f181.google.com ([209.85.216.181]:57819 "EHLO mail-qy0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755649Ab0GUFq0 (ORCPT ); Wed, 21 Jul 2010 01:46:26 -0400 Received: by qyk38 with SMTP id 38so2945788qyk.19 for ; Tue, 20 Jul 2010 22:46:25 -0700 (PDT) From: Ben Gamari To: Bruno Randolf , Bob Copeland Cc: linux-wireless@vger.kernel.org, ath5k-devel@lists.ath5k.org, johannes@sipsolutions.net Subject: Re: [PATCH/RFC 3/3] ath5k: trace resets In-Reply-To: <201007211417.23512.br1@einfach.org> References: <1279395336-856-1-git-send-email-me@bobcopeland.com> <201007211004.59372.br1@einfach.org> <20100721034150.GA16632@hash.localnet> <201007211417.23512.br1@einfach.org> Date: Wed, 21 Jul 2010 01:46:22 -0400 Message-ID: <87d3uhidzl.fsf@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, 21 Jul 2010 14:17:23 +0900, Bruno Randolf wrote: > but that's for all tracepoints all over the kernel... i think it's natural > that this takes some CPU time. note that on these boards even the 22Mbps are > limited by the CPU processing power. > The key word here is some. The numbers that you pointed out suggest that the effect here is quite large. I find it hard to believe that something isn't going wrong here. A single branch instruction really shouldn't be this onerous unless it's in a fast path, in which case it should probably be a compile-time option. What is the difference in image size between kernels with and without tracing? - Ben