Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759864Ab0FJWa2 (ORCPT ); Thu, 10 Jun 2010 18:30:28 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:60030 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754025Ab0FJWa1 (ORCPT ); Thu, 10 Jun 2010 18:30:27 -0400 MIME-Version: 1.0 In-Reply-To: <4C116652.8010408@athenacr.com> References: <20100610181042.GA19210@puku.stupidest.org> <4C116652.8010408@athenacr.com> Date: Thu, 10 Jun 2010 15:30:20 -0700 Message-ID: Subject: Re: Slow pty's (was Re: libdivecomputer interfaces?) From: Linus Torvalds To: Brian Bloniarz Cc: Chris Wedgwood , Greg KH , Alan Cox , OGAWA Hirofumi , Jef Driesen , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 976 Lines: 22 On Thu, Jun 10, 2010 at 3:25 PM, Brian Bloniarz wrote: > On 06/10/2010 02:10 PM, Chris Wedgwood wrote: >> >> this might not be related, but i have slow serial ports with NOHZ that >> goes away when i revert 39c0cbe2150cbd848a25ba6cdb271d1ad46818ad. > > Unrelated or not, I think Chris is right about this. Somewhere before > -rc1, the emulated serial console on my KVM instance became slow > to echo input. I just tested with the commit reverted and it's > back to normal. I suspect it's related. The tty subsystem clearly ends up depending on the timer tick to move things forward even if there are pending readers. So I suspect the slowness is very much related to the same issue. Linus -- 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/