From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753848AbbAEOF7 (ORCPT ); Mon, 5 Jan 2015 09:05:59 -0500 Received: from mail-qc0-f170.google.com ([209.85.216.170]:61356 "EHLO mail-qc0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753795AbbAEOF4 (ORCPT ); Mon, 5 Jan 2015 09:05:56 -0500 Message-ID: <54AA9A35.2000806@hurleysoftware.com> Date: Mon, 05 Jan 2015 09:05:41 -0500 From: Peter Hurley User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Vineet Gupta , "gregkh@linuxfoundation.org" CC: "linux-serial@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "robh@kernel.org" , "jslaby@suse.cz" , Arnd Bergmann Subject: Re: [PATCH v2 2/3] serial: 8250_early: prepare for dynamic BASE_BAUD References: <1420457437-17636-1-git-send-email-vgupta@synopsys.com> <1420457437-17636-3-git-send-email-vgupta@synopsys.com> <54AA8AFC.9020706@hurleysoftware.com> <54AA92C7.8070209@hurleysoftware.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/05/2015 08:52 AM, Vineet Gupta wrote: > On Monday 05 January 2015 07:04 PM, Peter Hurley wrote: >>> Also what do u think of the early IER optimization ? >> Seems ok except the commit changelog is wrong: IER is disabled twice per _line_. >> How did you profile it? It's ok if the answer is "seemed faster"; I'm just >> curious. > > Looking at the code yes this would be per line - but I vaguely remember seeing it > for every char - this was when debugging a systemC model for 8250. Its been a while... > I'd added prints in the model whenever IER would wiggle and it was just being > written with 0's again and again when in the early polling based printing mode. Maybe that was while running kgdb through serial8250_put_poll_char(), which is per-char. Regards, Peter Hurley