Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993449AbbEPIqY (ORCPT ); Sat, 16 May 2015 04:46:24 -0400 Received: from mail-la0-f46.google.com ([209.85.215.46]:33786 "EHLO mail-la0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1945943AbbEPIqT (ORCPT ); Sat, 16 May 2015 04:46:19 -0400 MIME-Version: 1.0 In-Reply-To: <20150514064407.GA9117@gmail.com> References: <1430732554-7294-1-git-send-email-jschoenh@amazon.de> <20150506082759.GA30019@gmail.com> <20150507102351.GA14347@gmail.com> <20150514064407.GA9117@gmail.com> Date: Sat, 16 May 2015 04:46:17 -0400 X-Google-Sender-Auth: TUMpYCjzsqF49FSKkNA8OmXKxzk Message-ID: Subject: Re: [PATCH] x86: skip delays during SMP initialization similar to Xen From: Len Brown To: Ingo Molnar Cc: =?UTF-8?Q?Jan_H=2E_Sch=C3=B6nherr?= , Thomas Gleixner , X86 ML , "linux-kernel@vger.kernel.org" , Anthony Liguori , Ingo Molnar , "H. Peter Anvin" , Tim Deegan , Gang Wei , Linus Torvalds Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1100 Lines: 31 On Thu, May 14, 2015 at 2:44 AM, Ingo Molnar wrote: > >> BTW. this time can be reduced by 7% (113 ms) by deleting >> announce_cpu(): >> >> [ 1.445815] x86: Booted up 4 nodes, 120 CPUs > > so that kind of info looks pretty useful, especially when there's > hangs/failures. I think the messages we print on failure are useful. I think the success case should be a 1-line summary. > I'm wondering what takes 113 msecs to print 120 CPUs - > that's about 1 msec per a few chars of printk produced, seems > excessive. Do you have any idea what's going on there? Does your > system print to a serial console perhaps? Yes, serial console -- that server is actually much closer to you than it is to me, it is in Finland:-) I should benchmark it, because 115200 should be faster... cheers, Len Brown, Intel Open Source Technology Center -- 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/