From owner-svn-src-head@freebsd.org Thu Mar 2 07:55:49 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 29B97CF5ACE; Thu, 2 Mar 2017 07:55:49 +0000 (UTC) (envelope-from mav@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id D3054BB1; Thu, 2 Mar 2017 07:55:48 +0000 (UTC) (envelope-from mav@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id v227tlQR068661; Thu, 2 Mar 2017 07:55:47 GMT (envelope-from mav@FreeBSD.org) Received: (from mav@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id v227tlfT068660; Thu, 2 Mar 2017 07:55:47 GMT (envelope-from mav@FreeBSD.org) Message-Id: <201703020755.v227tlfT068660@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mav set sender to mav@FreeBSD.org using -f From: Alexander Motin Date: Thu, 2 Mar 2017 07:55:47 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r314549 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 Mar 2017 07:55:49 -0000 Author: mav Date: Thu Mar 2 07:55:47 2017 New Revision: 314549 URL: https://svnweb.freebsd.org/changeset/base/314549 Log: Execute last ZIO of log commit synchronously. For short transactions overhead of context switch can be too large. Skipping it gives significant latency reduction. For large ones, including multiple ZIOs, latency is less critical, while throughput there may become limited by checksumming speed of single CPU core. To get best of both cases, execute last ZIO directly from calling thread context to save latency, while all others (if there are any) enqueue to taskqueues in traditional way. MFC after: 2 weeks Sponsored by: iXsystems, Inc. Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c Thu Mar 2 07:50:06 2017 (r314548) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zil.c Thu Mar 2 07:55:47 2017 (r314549) @@ -959,7 +959,7 @@ uint64_t zil_block_buckets[] = { * Calls are serialized. */ static lwb_t * -zil_lwb_write_start(zilog_t *zilog, lwb_t *lwb) +zil_lwb_write_start(zilog_t *zilog, lwb_t *lwb, boolean_t last) { lwb_t *nlwb = NULL; zil_chain_t *zilc; @@ -1060,6 +1060,8 @@ zil_lwb_write_start(zilog_t *zilog, lwb_ */ bzero(lwb->lwb_buf + lwb->lwb_nused, wsz - lwb->lwb_nused); + if (last) + lwb->lwb_zio->io_pipeline &= ~ZIO_STAGE_ISSUE_ASYNC; zio_nowait(lwb->lwb_zio); /* Kick off the write for the old log block */ /* @@ -1103,7 +1105,7 @@ cont: if (reclen > lwb_sp || (reclen + dlen > lwb_sp && lwb_sp < ZIL_MAX_LOG_DATA / 8 && (dlen % ZIL_MAX_LOG_DATA == 0 || lwb_sp < reclen + dlen % ZIL_MAX_LOG_DATA))) { - lwb = zil_lwb_write_start(zilog, lwb); + lwb = zil_lwb_write_start(zilog, lwb, B_FALSE); if (lwb == NULL) return (NULL); zil_lwb_write_init(zilog, lwb); @@ -1560,7 +1562,7 @@ zil_commit_writer(zilog_t *zilog) /* write the last block out */ if (lwb != NULL && lwb->lwb_zio != NULL) - lwb = zil_lwb_write_start(zilog, lwb); + lwb = zil_lwb_write_start(zilog, lwb, B_TRUE); zilog->zl_cur_used = 0;