Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932466Ab1EFRRF (ORCPT ); Fri, 6 May 2011 13:17:05 -0400 Received: from one.firstfloor.org ([213.235.205.2]:49027 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932412Ab1EFRRD (ORCPT ); Fri, 6 May 2011 13:17:03 -0400 Date: Fri, 6 May 2011 19:17:01 +0200 From: Andi Kleen To: Eric Dumazet Cc: Andi Kleen , Thomas Gleixner , john stultz , lkml , Paul Mackerras , "Paul E. McKenney" , Anton Blanchard , Ingo Molnar Subject: Re: [RFC] time: xtime_lock is held too long Message-ID: <20110506171701.GJ11636@one.firstfloor.org> References: <1304574244.32152.666.camel@edumazet-laptop> <1304576495.2943.40.camel@work-vm> <1304604284.3032.78.camel@edumazet-laptop> <1304608095.3032.95.camel@edumazet-laptop> <20110505210118.GI2925@one.firstfloor.org> <20110506165913.GF11636@one.firstfloor.org> <1304701778.3066.165.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1304701778.3066.165.camel@edumazet-laptop> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 858 Lines: 25 > Unless I am very mistaken, it cannot explain my original report of up to > 24.000 instructions waiting in ktime_get() Yes it's a different problem. Sorry for hijacking your thread. > > BTW, how many consecutive prefetch() a cpu can 'store/execute' before > throwing away hints ? It depends on the CPU. Older ones had a small number only. On the newer ones it tends to be limited by the various queues to memory, which are a shared resource (so it also depends on what the other threads/cores are doing) I normally assume as a rule of thumb < 50 -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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/