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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 EB0E2C43603 for ; Tue, 17 Dec 2019 03:35:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B69F6206E6 for ; Tue, 17 Dec 2019 03:35:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cg/Bv0Ac" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726767AbfLQDf1 (ORCPT ); Mon, 16 Dec 2019 22:35:27 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:24290 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726526AbfLQDf0 (ORCPT ); Mon, 16 Dec 2019 22:35:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576553725; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mmMjkohQcr4zZA7rYlo+cdoxbamsa0pcjMglzLFiziY=; b=cg/Bv0Ac/LnM1vrj6oJMOSt9PLSrFnVS2zFXWL99vMnRpMZCZEQyU9cOzRLDkgGwDOnvTE y7SWZ12u+WmQxJ60c7jhonsGAvJF+0RmYqFxQInFwU/PSn05hNEYNoxmgNidUixBTD3l8p wB2LWCVjd0DuzGx7/WMF2RFkPaGoqbI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-68-ofNXmEqlNFG1vQR4gwGkRA-1; Mon, 16 Dec 2019 22:35:22 -0500 X-MC-Unique: ofNXmEqlNFG1vQR4gwGkRA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 100BADBA3; Tue, 17 Dec 2019 03:35:21 +0000 (UTC) Received: from amt.cnet (ovpn-112-4.gru2.redhat.com [10.97.112.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id C964710018FF; Tue, 17 Dec 2019 03:35:20 +0000 (UTC) Received: from amt.cnet (localhost [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id D0AB810266B; Mon, 16 Dec 2019 19:14:45 -0200 (BRST) Received: (from marcelo@localhost) by amt.cnet (8.14.7/8.14.7/Submit) id xBGLEgqV003513; Mon, 16 Dec 2019 19:14:42 -0200 Date: Mon, 16 Dec 2019 19:14:41 -0200 From: Marcelo Tosatti To: Sebastian Andrzej Siewior Cc: John Kacur , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Clark Williams , Linux RT Users Subject: Re: [PATCH rt-tests] queuelat: use ARM implementation of gettick also for all !x86 archs Message-ID: <20191216211440.GB778@amt.cnet> References: <20191208210625.5999-1-ukleinek@debian.org> <20191212174604.xa6p46zhhii7qrhw@linutronix.de> <20191213230256.GA20494@amt.cnet> <20191216153449.sfxptmlyfthoianp@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191216153449.sfxptmlyfthoianp@linutronix.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Content-Transfer-Encoding: quoted-printable Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On Mon, Dec 16, 2019 at 04:34:49PM +0100, Sebastian Andrzej Siewior wrote= : > On 2019-12-13 21:02:56 [-0200], Marcelo Tosatti wrote: > > > > That freq. script reports here: > > > > |1555.184 1566.269 1566.498 1560.055 1593.149 1568.185 1583.807 1= 599.096 2574.546 2572.408 2573.849 2583.862 2619.402 1825.680 1847.264 18= 70.318 2552.102 1570.552 1589.650 1595.813 1590.253 1573.834 1589.438 159= 9.439 1770.963 1786.370 1814.918 1811.936 1828.277 1850.905 1861.976 1792= .809 > > > >=20 > > > > I guess I pick one=E2=80=A6 > > > >=20 > > > > Could someone please figure out the actual difference of clock_ge= ttime() > > > > vs rdtsc() so we know how important it is. Based on its current > > > > implementation, if memmove() takes >1sec then it ends up undetect= ed > > > > because only the ns of the timestamp are considered for. > >=20 > > /* Program parameters: > > * max_queue_len: maximum latency allowed, in nanoseconds (int). > > * cycles_per_packet: number of cycles to process one packet (int). > > * mpps(million-packet-per-sec): million packets per second (float). > > * tsc_freq_mhz: TSC frequency in MHz, as measured by TSC PIT > > * calibration=20 > > * (search for "Detected XXX MHz processor" in dmesg, and use the > > * integer part). > > */ > >=20 > > So you have to pass it "processor frequency" (you can change the name= s,=20 > > its TSC but thats x86 specific). The script grabs the processor > > frequency (so you have to adjust that the script to ARM). > >=20 > > And thats it. Please replace tsc_mhz -> processor_freq. >=20 > So the script reports the freq. from 1555.184 Mhz to 2574.546 Mhz. > And I doubt the numbers remain steady on today's x86 even with > gov=3Dperformance. > However, I asked for the frequency to be used on !x86 given the code we > have. It was fixed in hurry and you would have to use 1000 so that the > math keeps working. > Then I asked how much benefit of this complicated TSC calculation vs > clock_gettime() has. > I tried to use it myself but after 30secs I saw no output, it just ate > 100% and it seemed to do nothing. So I gave up. Then the simulated queue size was not exceeded, accordingly to the parameters you specified: * max_queue_len: maximum latency allowed, in nanoseconds (int). * cycles_per_packet: number of cycles to process one packet (int). * mpps(million-packet-per-sec): million packets per second (float). If you increase mpps or increase cycles_per_packet (or both),=20 or decrease max_queue_len, it should fail. Do you see that?