Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754563AbZFCIEZ (ORCPT ); Wed, 3 Jun 2009 04:04:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756647AbZFCIDs (ORCPT ); Wed, 3 Jun 2009 04:03:48 -0400 Received: from yw-out-2324.google.com ([74.125.46.29]:40846 "EHLO yw-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757047AbZFCIDp convert rfc822-to-8bit (ORCPT ); Wed, 3 Jun 2009 04:03:45 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=XOq+ow6OjY86slO7uh6U2QdoaLer/VDHoWF/fP0HCAD+AVW3g2RsnDOM1lLsvhZaee yhz+VYsWRMAECOT16TQ1k96rt1SDQanr8hzssKt+JFxU+kBXSDgHAmoW35zDBUDACS2D W8jiXm5oVv2A/mfC3bZQF64mpJnqK3Y0J9wow= MIME-Version: 1.0 In-Reply-To: <20090602100018.415b1dfc@lxorguk.ukuu.org.uk> 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> Date: Wed, 3 Jun 2009 04:03:46 -0400 Message-ID: <8bd0f97a0906030103i64bc1a9duc5aeaea7bd3f8365@mail.gmail.com> Subject: Re: [PATCH 04/11] Blackfin SPORT UART: fix overrun errors From: Mike Frysinger To: Alan Cox Cc: Mike Frysinger , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, uclinux-dist-devel@blackfin.uclinux.org, Cliff Cai , Bryan Wu Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1099 Lines: 28 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 -- 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/