From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Newsgroups: gmane.emacs.bugs Subject: bug#44674: 28.0.50; Adding current-cpu-time for performance tests Date: Mon, 16 Nov 2020 17:14:16 +0100 Message-ID: <0499BABB-AA02-43FA-89B8-59A7ECD03805@acm.org> References: Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.17\)) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="19359"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 44674@debbugs.gnu.org, Philipp Stephani To: Stefan Monnier Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Mon Nov 16 17:42:11 2020 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kehZw-0004pL-Ii for geb-bug-gnu-emacs@m.gmane-mx.org; Mon, 16 Nov 2020 17:42:11 +0100 Original-Received: from localhost ([::1]:55814 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kehZv-0002Ky-I1 for geb-bug-gnu-emacs@m.gmane-mx.org; Mon, 16 Nov 2020 11:42:07 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:60126) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1keh9i-0005kO-E6 for bug-gnu-emacs@gnu.org; Mon, 16 Nov 2020 11:15:02 -0500 Original-Received: from debbugs.gnu.org ([209.51.188.43]:45305) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1keh9h-0001Ro-Sd for bug-gnu-emacs@gnu.org; Mon, 16 Nov 2020 11:15:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1keh9h-0002JS-OR for bug-gnu-emacs@gnu.org; Mon, 16 Nov 2020 11:15:01 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 16 Nov 2020 16:15:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 44674 X-GNU-PR-Package: emacs Original-Received: via spool by 44674-submit@debbugs.gnu.org id=B44674.16055432698724 (code B ref 44674); Mon, 16 Nov 2020 16:15:01 +0000 Original-Received: (at 44674) by debbugs.gnu.org; 16 Nov 2020 16:14:29 +0000 Original-Received: from localhost ([127.0.0.1]:56850 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1keh9A-0002Gd-NC for submit@debbugs.gnu.org; Mon, 16 Nov 2020 11:14:29 -0500 Original-Received: from mail228c50.megamailservers.eu ([91.136.10.238]:59242 helo=mail36c50.megamailservers.eu) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1keh93-0002Fy-LI for 44674@debbugs.gnu.org; Mon, 16 Nov 2020 11:14:27 -0500 X-Authenticated-User: mattiase@bredband.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megamailservers.eu; s=maildub; t=1605543259; bh=KzzkqutXE3ekq1VVkrQsD+G3KnhzQoJYX+RFFwDWd9g=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From; b=VRmaCNqZ7lLEfqHYKqMr5s960rruMOXwYAu1eTbPeZlwLradFst0XWhv38w0pNWB+ W5p553Oqx7CZB/9Z+0BH4diNLKHqjJSjWZwyJyTrUSPlOUwJZk/sA2wE/OmbTOm6Bm 6YuoNyjxnRMbgwYsHOFSrgOvZH66huphugG0eUm0= Feedback-ID: mattiase@acm.or Original-Received: from stanniol.lan (c-064ae655.032-75-73746f71.bbcust.telenor.se [85.230.74.6]) (authenticated bits=0) by mail36c50.megamailservers.eu (8.14.9/8.13.1) with ESMTP id 0AGGEHnN003571; Mon, 16 Nov 2020 16:14:18 +0000 In-Reply-To: X-Mailer: Apple Mail (2.3445.104.17) X-CTCH-RefID: str=0001.0A782F1B.5FB2A55B.0090, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 X-CTCH-VOD: Unknown X-CTCH-Spam: Unknown X-CTCH-Score: 0.000 X-CTCH-Flags: 0 X-CTCH-ScoreCust: 0.000 X-CSC: 0 X-CHA: v=2.3 cv=Q4ysHL+a c=1 sm=1 tr=0 a=Ni+dBsiEfW2GqKMPYZim9A==:117 a=Ni+dBsiEfW2GqKMPYZim9A==:17 a=kj9zAlcOel0A:10 a=M51BFTxLslgA:10 a=iRZporoAAAAA:8 a=l3v9GiYDRwWU5_4XFmwA:9 a=CjuIK1q_8ugA:10 a=NOBgFS-JBQ2l-kSd6-zu:22 X-Origin-Country: SE X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:193440 Archived-At: 16 nov. 2020 kl. 16.27 skrev Stefan Monnier : > I expect that the time it takes to perform the `funcall` to get to = this > function is itself larger than the time it takes to run `Fcons`, so = I'm > not too worried about this overhead. Perhaps, but the lower the overhead, the shorter the intervals that can = effectively be measured. It would be a shame to build pointless latency = into the calling interface from the get-go. > `make_int` will return a fixnum when possible. Are you suggesting we > modulo-truncate the integer so it fits i a fixnum? As you say it's not worth doing so for 32 bits, but in case a full value = would require 64 bits, we should at least consider truncating it to 63. The values returned from clock, clock_gettime etc are generally = wrapping, which means that the user would need to know how to mask the = difference in case the timer wraps during a measured interval. This can = neatly be side-stepped by providing a function for computing the = duration from two sample points, eg, (cpu-time-duration CPU-TIME-1 CPU-TIME-2) which would apply the necessary modulo-reduction and return the duration = in seconds as a float. That way, we save the user the trouble to do (/ (logand (- CPU-TIME-2 CPU-TIME-1) (1- (ash 1 CPU-TIMER-BITS)) (float CPU-TIMER-FREQ)) and having to retrieve two system constants. > In my experience measuring CPU or wall clock time for things like > benchmarks is only meaningful if it's a non-trivial amount of time = (like > 0.1s or more), so the added cost of Fcons or allocating a bignum > is negligible. Being able to measure short intervals without too much noise can be = quite useful. Of course, CPU time is sometimes measured with much less = resolution than real time which sets an effective lower limit; 100 Hz = used to be the norm but it should be better these days.