Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760593Ab2EWUpG (ORCPT ); Wed, 23 May 2012 16:45:06 -0400 Received: from perches-mx.perches.com ([206.117.179.246]:58809 "EHLO labridge.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758666Ab2EWUpF (ORCPT ); Wed, 23 May 2012 16:45:05 -0400 Message-ID: <1337805903.1747.0.camel@joe2Laptop> Subject: Re: Excessive latency for dev_dbg? From: Joe Perches To: Alan Stern , Kay Sievers Cc: Kernel development list , Jason Baron , Thomas Gleixner , Greg KH Date: Wed, 23 May 2012 13:45:03 -0700 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.2- Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 786 Lines: 21 cc'ing Kay. On Wed, 2012-05-23 at 16:37 -0400, Alan Stern wrote: > I just tried doing some testing of 3.4. Sequences of literally > adjacent dev_dbg() calls -- with local interrupts disabled -- show up > in the log buffer spaced at time intervals between 1 and 4 > milliseconds! > > This is with CONFIG_DYNAMIC_DEBUG not enabled, and CONFIG_PRINTK_TIME, > CONFIG_PREEMPT, CONFIG_HIGH_RES_TIMERS, and CONFIG_HPET_TIMER all set > to y. > > What's going on here? Did printk suddenly slow down a lot? Or has the > timer code gone crazy? -- 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/