From nobody Sat Sep 03 03:26:27 2022 X-Original-To: freebsd-fs@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4MKKvK6lhCz4cBVY for ; Sat, 3 Sep 2022 03:26:37 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4MKKvK0SPZz3WHq for ; Sat, 3 Sep 2022 03:26:36 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.16.1/8.16.1) with ESMTPS id 2833QSuc039340 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sat, 3 Sep 2022 06:26:31 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by tom.home (8.16.1/8.16.1/Submit) id 2833QRhl039339; Sat, 3 Sep 2022 06:26:27 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Sat, 3 Sep 2022 06:26:27 +0300 From: Konstantin Belousov To: Rick Macklem Cc: FreeBSD Filesystems Subject: Re: RFC: multiple concurrent I/O ops for copy_file_range(2) Message-ID: References: List-Id: Filesystems List-Archive: https://lists.freebsd.org/archives/freebsd-fs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-fs@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on tom.home X-Rspamd-Queue-Id: 4MKKvK0SPZz3WHq X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=gmail.com (policy=none); spf=softfail (mx1.freebsd.org: 2001:470:d5e7:1::1 is neither permitted nor denied by domain of kostikbel@gmail.com) smtp.mailfrom=kostikbel@gmail.com X-Spamd-Result: default: False [-2.99 / 15.00]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.99)[-0.993]; MIME_GOOD(-0.10)[text/plain]; DMARC_POLICY_SOFTFAIL(0.10)[gmail.com : No valid SPF, No valid DKIM,none]; FREEMAIL_ENVFROM(0.00)[gmail.com]; RCPT_COUNT_TWO(0.00)[2]; R_DKIM_NA(0.00)[]; MLMMJ_DEST(0.00)[freebsd-fs@freebsd.org]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US]; FROM_EQ_ENVFROM(0.00)[]; TO_DN_ALL(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; FROM_HAS_DN(0.00)[]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_FROM(0.00)[gmail.com]; R_SPF_SOFTFAIL(0.00)[~all]; HAS_XAW(0.00)[]; RCVD_TLS_LAST(0.00)[] X-ThisMailContainsUnwantedMimeParts: N On Sat, Sep 03, 2022 at 03:11:03AM +0000, Rick Macklem wrote: > Hi, > > A recent discussion involving copy_file_range(2) performance > included a suggestion that, maybe, copying of subranges > should be done concurrently. > > Although I cannot be 100% sure, I think that this would > involve using multiple kernel threads (taskqueue or similar) > to issue I/O operations on the file system(s) for blocks > (of f_iosize maybe?) concurrently, to improve performance. > > Doing this in a system call is unusual, to say the least but, then, > copy_file_range(2) is an unusual system call to begin with. > > I have not attempted to code this up as of yet. > > So, what do others think of this idea? > Note that UFS does not understand more than one stream of writes to single vnode. The result could be a severe fragmentation, which is relevant even for SSDs (due to large internal block size).