From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757461AbYG1XQt (ORCPT ); Mon, 28 Jul 2008 19:16:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752493AbYG1XQf (ORCPT ); Mon, 28 Jul 2008 19:16:35 -0400 Received: from gw.goop.org ([64.81.55.164]:49573 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752486AbYG1XQe (ORCPT ); Mon, 28 Jul 2008 19:16:34 -0400 Message-ID: <488E534F.2030204@goop.org> Date: Mon, 28 Jul 2008 16:16:31 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Ingo Molnar CC: Jens Axboe , Andi Kleen , Linux Kernel Mailing List Subject: x86: Is there still value in having a special tlb flush IPI vector? X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now that normal smp_function_call is no longer an enormous bottleneck, is there still value in having a specialised IPI vector for tlb flushes? It seems like quite a lot of duplicate code. The 64-bit tlb flush multiplexes the various cpus across 8 vectors to increase scalability. If this is a big issue, then the smp function call code can (and should) do the same thing. (Though looking at it more closely, the way the code uses the 8 vectors is actually a less general way of doing what smp_call_function is doing anyway.) Thoughts? (And uv should definitely be hooking pvops if it wants its own flush_tlb_others; vsmp sets the precedent for a subarch-like use of pvops.) J