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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44AA6C77B61 for ; Sat, 8 Apr 2023 20:47:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229459AbjDHUrI (ORCPT ); Sat, 8 Apr 2023 16:47:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229451AbjDHUrH (ORCPT ); Sat, 8 Apr 2023 16:47:07 -0400 Received: from mx10.gouders.net (mx10.gouders.net [202.61.206.94]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DECFA5271 for ; Sat, 8 Apr 2023 13:47:06 -0700 (PDT) Received: from localhost (ip-109-40-241-98.web.vodafone.de [109.40.241.98]) (authenticated bits=0) by mx10.gouders.net (8.17.1.9/8.16.1) with ESMTPSA id 338KkpSs031689 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sat, 8 Apr 2023 22:46:52 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gouders.net; s=gnet; t=1680986812; bh=ekB2ZWk1EALjFPLxhfDPAa+7PpFwgf9dOpfOQ9kBPeM=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=HxnbeUX8tC+9RfenEf9C5rX7RdNqTLfihCKosVCRqqDxV9oAoDmKHD37LHjdNLAPw GakkKK0YogM71bAp60No07tLWVDPs2cY2fwcZVkghOCutIExAB8+XfUyzRp2iqBtdQ jKkYN7dpRVfiRZHcaye8ThUkfmb6462Wd+snoKU0= From: Dirk Gouders To: Eli Zaretskii Cc: alx.manpages@gmail.com, cjwatson@debian.org, linux-man@vger.kernel.org, help-texinfo@gnu.org, nabijaczleweli@nabijaczleweli.xyz, g.branden.robinson@gmail.com, groff@gnu.org Subject: Re: Accessibility of man pages In-Reply-To: <83bkjym9bw.fsf@gnu.org> (Eli Zaretskii's message of "Sat, 08 Apr 2023 23:02:11 +0300") References: <073413e2-7d35-f0d7-26eb-f66908d7af6a@gmail.com> <834jpuuc1a.fsf@gnu.org> <6ea6d1fe-375f-487a-b524-adc86880d3de@gmail.com> <83sfddqvk3.fsf@gnu.org> <390c8bba-6089-b006-eaf1-9fcfda2c6c4b@gmail.com> <837cumonv9.fsf@gnu.org> <78ca213f-8723-dccb-e131-081400c28e5d@gmail.com> <83bkjym9bw.fsf@gnu.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) Date: Sat, 08 Apr 2023 22:46:46 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org Eli Zaretskii writes: >> From: Dirk Gouders >> Cc: Colin Watson , Eli Zaretskii , >> linux-man@vger.kernel.org, help-texinfo@gnu.org, >> nabijaczleweli@nabijaczleweli.xyz, g.branden.robinson@gmail.com, >> groff@gnu.org >> Date: Sat, 08 Apr 2023 21:48:13 +0200 >> >> $ find /usr/share/man -type f -exec bzgrep -l RLIMIT_NOFILE {} \; >> /usr/share/man/man1/runuser.1.bz2 >> /usr/share/man/man1/su.1.bz2 >> /usr/share/man/man1/nghttpx.1.bz2 >> /usr/share/man/man3/getdtablesize.3.bz2 >> /usr/share/man/man3/mq_open.3.bz2 >> /usr/share/man/man3/errno.3.bz2 >> /usr/share/man/man3/sysconf.3.bz2 >> /usr/share/man/man3p/getrlimit.3p.bz2 >> /usr/share/man/man3p/sysconf.3p.bz2 >> /usr/share/man/man3p/posix_spawn_file_actions_addclose.3p.bz2 >> /usr/share/man/man0p/sys_resource.h.0p.bz2 >> /usr/share/man/man2/pidfd_open.2.bz2 >> /usr/share/man/man2/poll.2.bz2 >> /usr/share/man/man2/getrlimit.2.bz2 >> /usr/share/man/man2/open.2.bz2 >> /usr/share/man/man2/select.2.bz2 >> /usr/share/man/man2/fcntl.2.bz2 >> /usr/share/man/man2/seccomp_unotify.2.bz2 >> /usr/share/man/man2/dup.2.bz2 >> /usr/share/man/man2/pidfd_getfd.2.bz2 >> /usr/share/man/man7/fanotify.7.bz2 >> /usr/share/man/man7/capabilities.7.bz2 >> /usr/share/man/man7/unix.7.bz2 >> /usr/share/man/man5/proc.5.bz2 >> >> Yes, it's very slow but close to `man -K`: >> >> find... man -K... >> >> real 107.45 real 96.34 >> user 117.06 user 70.11 >> sys 14.43 sys 26.86 >> >> [a thought later] >> >> Oh, I found something much faster: >> >> $ time -p find /usr/share/man -type f | xargs bzgrep -l RLIMIT_NOFILE >> [snip] >> >> real 24.30 >> user 32.34 >> sys 6.84 >> >> Hmm, perhaps, someone has an explanation for this? > > Multiprocessing, obviously. Your CPU has more than one execution > unit, so the pipe via xargs runs 'find' and 'bzgrep' in parallel on > two different execution units. By contrast, "find -exec" runs them > sequentially, in a single thread. Yes, that must be it, thanks. I noticed `man -K...` uses up to four CPUs in parallel and therefore was unsure. With your explanation, we can get even faster: $ time -p find /usr/share/man -type f | xargs -P 6 bzgrep -l RLIMIT_NOFILE [snip] real 7.56 user 32.97 sys 7.02 Dirk PS: Colin, too late, I noticed a Mail-Followup-To Header in your mail. For the future: Is it correct that in such a case one should use that recipient list (without your address) -- even if he replies to something you wrote? In that case: I'm sorry I did that wrong.