From owner-dev-commits-src-main@freebsd.org Thu Jan 21 04:19:00 2021 Return-Path: Delivered-To: dev-commits-src-main@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 46A544E8873; Thu, 21 Jan 2021 04:19:00 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (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-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4DLq041XwDz4qSg; Thu, 21 Jan 2021 04:19:00 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (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 mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 27F67257E1; Thu, 21 Jan 2021 04:19:00 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 10L4J0Ml075353; Thu, 21 Jan 2021 04:19:00 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 10L4J0oT075352; Thu, 21 Jan 2021 04:19:00 GMT (envelope-from git) Date: Thu, 21 Jan 2021 04:19:00 GMT Message-Id: <202101210419.10L4J0oT075352@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Alexander Motin Subject: git: ff751ee05c93 - main - Remove FirstBurstLength limit for software iSCSI. MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: mav X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: ff751ee05c939eceab25c26ad60b1d56f989aec9 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-main@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for the main branch of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 Jan 2021 04:19:00 -0000 The branch main has been updated by mav: URL: https://cgit.FreeBSD.org/src/commit/?id=ff751ee05c939eceab25c26ad60b1d56f989aec9 commit ff751ee05c939eceab25c26ad60b1d56f989aec9 Author: Alexander Motin AuthorDate: 2021-01-21 02:33:14 +0000 Commit: Alexander Motin CommitDate: 2021-01-21 04:17:12 +0000 Remove FirstBurstLength limit for software iSCSI. For hardware offload solicited data may potentially be handled more efficiently than unsolicited due to direct data placement. Or there can be some unsolicited write buffering limitations. It may create situations where FirstBurstLength limit is really useful. Software driver though has no those factors, having to do memcopy() any way and having no so hard limit on the temporary storage. Same time more active use of unsolicited transfers allows to avoid some of Ready To Transfer (R2T) PDU round-trip times and processing. This change effectively doubles from 64KB to 128KB the maximum size of write command that can be transferred within one link RTT. Tests of (64KB, 128KB] QD1 writes mixed with simultaneous QD8 reads over the same connection, increasing RTT, shows almost double write speed and half latency, while we should be able to afford few megabytes of RAM for additional buffering on a target these days. MFC after: 2 weeks Sponsored by: iXsystems, Inc. --- sys/dev/iscsi/icl_soft.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/dev/iscsi/icl_soft.c b/sys/dev/iscsi/icl_soft.c index bd4d9db81bb0..41d20b4abf69 100644 --- a/sys/dev/iscsi/icl_soft.c +++ b/sys/dev/iscsi/icl_soft.c @@ -1523,7 +1523,7 @@ icl_soft_limits(struct icl_drv_limits *idl) idl->idl_max_recv_data_segment_length = 128 * 1024; idl->idl_max_send_data_segment_length = 128 * 1024; idl->idl_max_burst_length = 262144; - idl->idl_first_burst_length = 65536; + idl->idl_first_burst_length = idl->idl_max_burst_length; return (0); }