Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755813AbZFCIqT (ORCPT ); Wed, 3 Jun 2009 04:46:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751586AbZFCIqH (ORCPT ); Wed, 3 Jun 2009 04:46:07 -0400 Received: from nwd2mail10.analog.com ([137.71.25.55]:40767 "EHLO nwd2mail10.analog.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751985AbZFCIqF convert rfc822-to-8bit (ORCPT ); Wed, 3 Jun 2009 04:46:05 -0400 From: "Cai, Cliff" X-IronPort-AV: E=Sophos;i="4.41,297,1241409600"; d="scan'208";a="88331224" X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-Class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Subject: RE: [PATCH 04/11] Blackfin SPORT UART: fix overrun errors Date: Wed, 3 Jun 2009 16:49:41 +0800 Message-ID: <0F1B54C89D5F954D8535DB252AF412FA0422906C@chinexm1.ad.analog.com> In-Reply-To: <8bd0f97a0906030103i64bc1a9duc5aeaea7bd3f8365@mail.gmail.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [PATCH 04/11] Blackfin SPORT UART: fix overrun errors Thread-Index: AcnkIdTq/2eZfm3ZRFGtgpDbJsXiKAABi8Yw References: <1243926700-30485-1-git-send-email-vapier@gentoo.org> <1243926700-30485-4-git-send-email-vapier@gentoo.org> <20090602100018.415b1dfc@lxorguk.ukuu.org.uk> <8bd0f97a0906030103i64bc1a9duc5aeaea7bd3f8365@mail.gmail.com> To: "Mike Frysinger" , "Alan Cox" CC: "Mike Frysinger" , , , , "Bryan Wu" X-OriginalArrivalTime: 03 Jun 2009 08:46:06.0699 (UTC) FILETIME=[BC1303B0:01C9E427] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1580 Lines: 46 >-----Original Message----- >From: Mike Frysinger [mailto:vapier.adi@gmail.com] >Sent: Wednesday, June 03, 2009 4:04 PM >To: Alan Cox >Cc: Mike Frysinger; linux-serial@vger.kernel.org; >linux-kernel@vger.kernel.org; >uclinux-dist-devel@blackfin.uclinux.org; Cai, Cliff; Bryan Wu >Subject: Re: [PATCH 04/11] Blackfin SPORT UART: fix overrun errors > >On Tue, Jun 2, 2009 at 05:00, Alan Cox wrote: >> On Tue, ?2 Jun 2009 03:11:33 -0400 Mike Frysinger wrote: >>> From: Cliff Cai >>> >>> Push the ty_flip_buffer_push() call from the IRQ handler to a timer >>> so as to improve performance and decrease likelihood of overruns. >> >> This should have no effect on a modern kernel. > >well, we wouldnt be making changes if we werent seeing data >overruns today > >> There is 64K of queueing between you and the ldisc nowdays. > >i dont think that really matters ... we do too much work in >the interrupt and so we miss new data > >> Furthermore unless you set tty->low_latency the kernel already >> basically does this aggregation for you as the buffer push queues >> stuff for the ldisc to wake up and process. > >i guess we could try setting the low_latency bool instead and >see if that fixes things -mike > The overrrun problem doesn't exist even without my patch now,so I will drop it. Thanks Cliff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/