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=-5.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 1227AC3F2D7 for ; Wed, 4 Mar 2020 17:56:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E0E2024671 for ; Wed, 4 Mar 2020 17:56:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="W97TUuPp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730081AbgCDR4P (ORCPT ); Wed, 4 Mar 2020 12:56:15 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:32433 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729923AbgCDR4P (ORCPT ); Wed, 4 Mar 2020 12:56:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583344574; 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=i1Cgn4yp7EaKnNlZymNOD5ifYaNSlnfx75qVUEAj3xM=; b=W97TUuPpyA/HiwsRLEmkj7Omy7Cnlam2mFAJGAMmvII4C9/mRcGYqaS4sLeTbq1GrO9K9h GlIZASUTdob8fPBuevzTF6twBaZsjqXX+ml1GL1vZqLtJ/g2A+hw630BjM6gHEZtoc4ISZ aTFV85wPE5dDbvXEN7ssV6/xf6In0pQ= 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-203-7y7GWO5UPeCY2a9BNTDovA-1; Wed, 04 Mar 2020 12:56:10 -0500 X-MC-Unique: 7y7GWO5UPeCY2a9BNTDovA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D99F9801E76; Wed, 4 Mar 2020 17:56:07 +0000 (UTC) Received: from ws.net.home (ovpn-204-202.brq.redhat.com [10.40.204.202]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 45A915C548; Wed, 4 Mar 2020 17:55:59 +0000 (UTC) Date: Wed, 4 Mar 2020 18:55:56 +0100 From: Karel Zak To: Greg Kroah-Hartman Cc: Ian Kent , Miklos Szeredi , David Howells , Christian Brauner , James Bottomley , Steven Whitehouse , Miklos Szeredi , viro , Christian Brauner , Jann Horn , "Darrick J. Wong" , Linux API , linux-fsdevel , lkml Subject: Re: [PATCH 00/17] VFS: Filesystem information and notifications [ver #17] Message-ID: <20200304175556.45dsgxumv4ubz7qy@ws.net.home> References: <0403cda7345e34c800eec8e2870a1917a8c07e5c.camel@themaw.net> <1509948.1583226773@warthog.procyon.org.uk> <20200303113814.rsqhljkch6tgorpu@ws.net.home> <20200303130347.GA2302029@kroah.com> <33d900c8061c40f70ba2b9d1855fd6bd1c2b68bb.camel@themaw.net> <20200304152241.iaiulvl5xisnuxp6@ws.net.home> <20200304164913.GB1763256@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20200304164913.GB1763256@kroah.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Content-Transfer-Encoding: quoted-printable Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Mar 04, 2020 at 05:49:13PM +0100, Greg Kroah-Hartman wrote: > On Wed, Mar 04, 2020 at 04:22:41PM +0100, Karel Zak wrote: > > $ strace -e openat,read,close -c ps aux > > ... > > % time seconds usecs/call calls errors syscall > > ------ ----------- ----------- --------- --------- ---------------- > > 43.32 0.004190 4 987 read > > 31.42 0.003039 3 844 4 openat > > 25.26 0.002443 2 842 close > > ------ ----------- ----------- --------- --------- ---------------- > > 100.00 0.009672 2673 4 total > >=20 > > $ strace -e openat,read,close -c lsns > > ... > > % time seconds usecs/call calls errors syscall > > ------ ----------- ----------- --------- --------- ---------------- > > 39.95 0.001567 2 593 openat > > 30.93 0.001213 2 597 close > > 29.12 0.001142 3 365 read > > ------ ----------- ----------- --------- --------- ---------------- > > 100.00 0.003922 1555 total > >=20 > >=20 > > $ strace -e openat,read,close -c lscpu > > ... > > % time seconds usecs/call calls errors syscall > > ------ ----------- ----------- --------- --------- ---------------- > > 44.67 0.001480 7 189 52 openat > > 34.77 0.001152 6 180 read > > 20.56 0.000681 4 140 close > > ------ ----------- ----------- --------- --------- ---------------- > > 100.00 0.003313 509 52 total >=20 > As a "real-world" test, would you recommend me converting one of the > above tools to my implementation of readfile to see how/if it actually > makes sense, or do you have some other tool you would rather see me try= ? See lib/path.c and lib/sysfs.c in util-linux (https://github.com/karelzak= /util-linux).=20 For example ul_path_read() and ul_path_scanf().=20 We use it for lsblk, lsmem, lscpu, etc. =A0$ git grep -c ul_path_read misc-utils/lsblk.c sys-utils/lscpu.c misc-utils/lsblk.c:30 sys-utils/lscpu.c:31 We're probably a little bit off-topic here, no problem to continue on util-linux@vger.kernel.org or by private mails. Thanks! Karel --=20 Karel Zak http://karelzak.blogspot.com