From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9D1EC04EBB for ; Sun, 25 Nov 2018 03:25:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 88F7D20855 for ; Sun, 25 Nov 2018 03:25:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88F7D20855 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=telegraphics.com.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726966AbeKYOPZ (ORCPT ); Sun, 25 Nov 2018 09:15:25 -0500 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:37566 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726560AbeKYOPY (ORCPT ); Sun, 25 Nov 2018 09:15:24 -0500 Received: from localhost (localhost.localdomain [127.0.0.1]) by kvm5.telegraphics.com.au (Postfix) with ESMTP id AE1F7224AE; Sat, 24 Nov 2018 22:25:17 -0500 (EST) Date: Sun, 25 Nov 2018 14:25:25 +1100 (AEDT) From: Finn Thain To: Michael Schmitz cc: Geert Uytterhoeven , Kars de Jong , Philip Blundell , Andreas Schwab , Arnd Bergmann , Stephen N Chivers , Thomas Gleixner , Daniel Lezcano , John Stultz , Linus Walleij , linux-m68k , Linux Kernel Mailing List Subject: Re: [RFC PATCH v2 09/14] m68k: hp300: Remove hp300_gettimeoffset() In-Reply-To: <36b78174-5038-a1ac-4c70-d84a34edd275@gmail.com> Message-ID: References: <36b78174-5038-a1ac-4c70-d84a34edd275@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 25 Nov 2018, Michael Schmitz wrote: > > We can benchmark gettimeofday syscalls on elgar but is that hardware > > representative of other relevant models? > > I suppose the CIA is on the main board, so running with the slower clock > speed that you'd see with a vanilla Amiga without 060 accelerator board. > Ought to be representative enough? > Not really. An accelerated CPU clock exaggerates the slowdown factor, given the fixed 0.7 MHz CIA clock. The "(ticks > jiffy_ticks / 2)" conditional won't make anything worse even if interrupt latency is already too high, so I'm inclined towards the more prudent option. This patch series is already complicated enough. In anycase, I'd prefer not to speculate about interrupt priorities or latencies when the list probably has people who know the answers. --