Date: Wed, 26 Jul 2017 16:30:09 +0000 (UTC) From: Alexander Motin <mav@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r321543 - stable/11/cddl/contrib/opensolaris/cmd/zdb Message-ID: <201707261630.v6QGU9TN068516@repo.freebsd.org>
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Author: mav Date: Wed Jul 26 16:30:09 2017 New Revision: 321543 URL: https://svnweb.freebsd.org/changeset/base/321543 Log: MFC r318812: MFV r316860: 7545 zdb should disable reference tracking illumos/illumos-gate@4dd77f9e38ef05b39db128ff7608d926fd3218c6 https://github.com/illumos/illumos-gate/commit/4dd77f9e38ef05b39db128ff7608d926fd3218c6 https://www.illumos.org/issues/7545 When evicting from the ARC, we manipulate some refcount_t's, e.g. arcs_size. When using zdb to examine a large amount of data (e.g. zdb -bb on a large pool with small blocks), the ARC may have a large number of entries. If reference tracking is enabled, there will be ~1 reference for each block in the ARC. When evicting, we decrement the refcount and have to search all the references to find the one that we are removing, which is very slow. Since zdb is typically used to find problems with the on-disk format, and not with the code it is running, we should disable reference tracking in zdb. Reviewed by: Dan Kimmel <dan.kimmel@delphix.com> Reviewed by: Steve Gonczi <steve.gonczi@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Approved by: Robert Mustacchi <rm@joyent.com> Author: Matthew Ahrens <mahrens@delphix.com> Modified: stable/11/cddl/contrib/opensolaris/cmd/zdb/zdb.c Directory Properties: stable/11/ (props changed) Modified: stable/11/cddl/contrib/opensolaris/cmd/zdb/zdb.c ============================================================================== --- stable/11/cddl/contrib/opensolaris/cmd/zdb/zdb.c Wed Jul 26 16:28:05 2017 (r321542) +++ stable/11/cddl/contrib/opensolaris/cmd/zdb/zdb.c Wed Jul 26 16:30:09 2017 (r321543) @@ -75,10 +75,12 @@ DMU_OT_ZAP_OTHER : DMU_OT_NUMTYPES)) #ifndef lint +extern int reference_tracking_enable; extern boolean_t zfs_recover; extern uint64_t zfs_arc_max, zfs_arc_meta_limit; extern int zfs_vdev_async_read_max_active; #else +int reference_tracking_enable; boolean_t zfs_recover; uint64_t zfs_arc_max, zfs_arc_meta_limit; int zfs_vdev_async_read_max_active; @@ -3695,6 +3697,11 @@ main(int argc, char **argv) * For good performance, let several of them be active at once. */ zfs_vdev_async_read_max_active = 10; + + /* + * Disable reference tracking for better performance. + */ + reference_tracking_enable = B_FALSE; kernel_init(FREAD); g_zfs = libzfs_init();
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