FreeBSD 10.0-BETA1 #8 r256765M spend too much time in locks
Vitalij Satanivskij
satan at ukr.net
Thu Oct 24 10:43:09 UTC 2013
Another strange's disabling zfs prefetch gives perfomance boost, at last LA now 4-10 and not 10-20 ^)
Look's like system and software need more memory to work quickly, but I dont understand why on newer version of freebsd
memory size used by ARC laways == vfs.zfs.arc_max and never go lower?
For example vfs.zfs.arc_min=34359738368 and vfs.zfs.arc_max=85899345920 on early revision's actual size of arc was
40-76gb depend's on day time day of week (and load in that's times) but now arc grows up to high limit and stay here.
Is changes in vm (I know about vmem) also change priority of memory alocation for diferent subsytems?
Vitalij Satanivskij wrote:
VS>
VS>
VS> EEE forget to notice - old system have none compression on main zfs
VS>
VS>
VS>
VS> Vitalij Satanivskij wrote:
VS> VS> Hello.
VS> VS>
VS> VS> After upgrading system from old current (r245701) to fresh current r255173 (than switch to stable/10 r256765M)
VS> VS> found some strange system behavior:
VS> VS>
VS> VS> Diff from r256765M anf r256765 is
VS> VS> Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
VS> VS> ===================================================================
VS> VS> --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c (revision 256765)
VS> VS> +++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c (working copy)
VS> VS> @@ -5147,7 +5147,7 @@
VS> VS> len = l2hdr->b_asize;
VS> VS> cdata = zio_data_buf_alloc(len);
VS> VS> csize = zio_compress_data(ZIO_COMPRESS_LZ4, l2hdr->b_tmp_cdata,
VS> VS> - cdata, l2hdr->b_asize, (size_t)SPA_MINBLOCKSIZE);
VS> VS> + cdata, l2hdr->b_asize, (size_t)(1ULL << l2hdr->b_dev->l2ad_vdev->vdev_ashift));
VS> VS>
VS> VS> if (csize == 0) {
VS> VS> /* zero block, indicate that there's nothing to write */
VS> VS>
VS> VS>
VS> VS> But same situation was befor patch.
VS> VS>
VS> VS>
VS> VS> System load to high
VS> VS> CPU: 6.8% user, 0.0% nice, 57.3% system, 0.8% interrupt, 35.1% idle
VS> VS>
VS> VS> hotkernel (dtrace script) says
VS> VS>
VS> VS> kernel`__mtx_unlock_flags 292 0.3%
VS> VS> kernel`__mtx_lock_flags 315 0.3%
VS> VS> zfs.ko`lzjb_compress 349 0.3%
VS> VS> kernel`__rw_wlock_hard 686 0.7%
VS> VS> kernel`spinlock_exit 1050 1.0%
VS> VS> kernel`vmem_xalloc 7516 7.3%
VS> VS> kernel`_sx_xlock_hard 8664 8.5%
VS> VS> kernel`acpi_cpu_c1 9737 9.5%
VS> VS> kernel`cpu_idle 20189 19.7%
VS> VS> kernel`__mtx_lock_sleep 45952 44.9%
VS> VS>
VS> VS>
VS> VS>
VS> VS> Trying to understand where is a problem I'm build kernel with lock profiling.
VS> VS>
VS> VS> and get some data (for one minute )
VS> VS>
VS> VS> (file attached)
VS> VS>
VS> VS> using agregation find most lock's is in
VS> VS>
VS> VS> 14,159818 /usr/src/sys/kern/subr_vmem.c:1128(sleep mutex:kmem arena)
VS> VS> 9,553523 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:1597(sx:buf_hash_table.ht_locks[i].ht_lock)
VS> VS> 8,386943 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:3541(sx:l2arc_buflist_mtx)
VS> VS> 8,110206 /usr/src/sys/kern/subr_vmem.c:1230(sleep mutex:kmem arena)
VS> VS> 5,909429 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:1969(sx:arc_mru->arcs_locks[i].arcs_lock)
VS> VS> 5,452206 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:1969(sx:arc_mfu->arcs_locks[i].arcs_lock)
VS> VS> 5,050224 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/txg.c:303(sx:tx->tx_cpu[c].tc_open_lock)
VS> VS> 4,232819 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:891(sx:buf_hash_table.ht_locks[i].ht_lock)
VS> VS> 4,211348 /usr/src/sys/kern/vfs_subr.c:2101(lockmgr:zfs)
VS> VS> 4,011656 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:862(sx:buf_hash_table.ht_locks[i].ht_lock)
VS> VS> 3,823698 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:2009(sx:arc_eviction_mtx)
VS> VS> 2,697344 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c:126(sx:h->hash_mutexes[i])
VS> VS> 2,343242 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:1256(sx:arc_mfu->arcs_locks[i].arcs_lock)
VS> VS> 1,752713 /usr/src/sys/kern/vfs_lookup.c:707(lockmgr:zfs)
VS> VS> 1,580856 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c:1136(sx:zfsvfs->z_hold_mtx[i])
VS> VS> 1,534242 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:1291(sx:arc_mfu->arcs_locks[i].arcs_lock)
VS> VS> 1,331583 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c:129(sx:db->db_mtx)
VS> VS> 1,105058 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c:427(sx:vq->vq_lock)
VS> VS> 1,080855 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c:396(sx:vq->vq_lock)
VS> VS> 0,858568 /usr/src/sys/kern/vfs_cache.c:488(rw:Name Cache)
VS> VS> 0,831652 /usr/src/sys/vm/vm_kern.c:344(rw:kmem vm object)
VS> VS> 0,815439 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:1845(sx:buf_hash_table.ht_locks[i].ht_lock)
VS> VS> 0,812613 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c:1256(sx:arc_mru->arcs_locks[i].arcs_lock)
VS> VS> 0,794274 /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c:1529(lockmgr:zfs)
VS> VS> 0,669845 /usr/src/sys/vm/uma_core.c:2097(sleep mutex:zio_cache)
VS> VS>
VS> VS>
VS> VS>
VS> VS>
VS> VS> Short system description
VS> VS> CPU E5-1650
VS> VS> MEM 128Gb ddr3-1600
VS> VS>
VS> VS> Storage subsystem
VS> VS>
VS> VS> 36x1Tb WD RE4 drives on LSI SAS2308 Controler
VS> VS> 3x180Gb Intel ssd 530 series as l2 cache
VS> VS>
VS> VS>
VS> VS> POOL is 18 mirrors, two drives in ich mirror and 3 cache devices
VS> VS>
VS> VS> eg.
VS> VS> ....
VS> VS> mirror-14 ONLINE 0 0 0
VS> VS> gpt/disk28 ONLINE 0 0 0
VS> VS> gpt/disk29 ONLINE 0 0 0
VS> VS> mirror-15 ONLINE 0 0 0
VS> VS> gpt/disk30 ONLINE 0 0 0
VS> VS> gpt/disk31 ONLINE 0 0 0
VS> VS> mirror-16 ONLINE 0 0 0
VS> VS> gpt/disk32 ONLINE 0 0 0
VS> VS> gpt/disk33 ONLINE 0 0 0
VS> VS> mirror-17 ONLINE 0 0 0
VS> VS> gpt/disk34 ONLINE 0 0 0
VS> VS> gpt/disk35 ONLINE 0 0 0
VS> VS> cache
VS> VS> ada1 ONLINE 0 0 0
VS> VS> ada2 ONLINE 0 0 0
VS> VS> ada3 ONLINE 0 0 0
VS> VS>
VS> VS>
VS> VS> POOL have two ZFS
VS> VS>
VS> VS> main with options (diffs from default) -
VS> VS> compression lz4
VS> VS> secondarycache all
VS> VS> sync disabled
VS> VS>
VS> VS> Data size for it around 6Tb (compresed) eg
VS> VS> disk1 refcompressratio 1.56x -
VS> VS> disk1 written 5,99T -
VS> VS> disk1 logicalused 10,8T -
VS> VS> disk1 logicalreferenced 9,32T -
VS> VS>
VS> VS>
VS> VS> and another with options
VS> VS> recordsize 4K, before it was 32k, but internal software use data blocks mostly 4k so we try to change (without real data realocate )
VS> VS> compresion -s off
VS> VS> sync disabled
VS> VS> secondarycache all
VS> VS>
VS> VS> DATA size on it around 1.4Tb
VS> VS>
VS> VS> ARC configured to use max 80Gb
VS> VS>
VS> VS> top most time looks like this
VS> VS>
VS> VS> Mem: 14G Active, 13G Inact, 94G Wired, 497M Cache, 3297M Buf, 2214M Free
VS> VS> ARC: 80G Total, 2010M MFU, 70G MRU, 49M Anon, 3822M Header, 4288M Other
VS> VS>
VS> VS>
VS> VS> LA's - around 10-20 depend on day time.
VS> VS>
VS> VS>
VS> VS> zpool iostat disk1 1
VS> VS> capacity operations bandwidth
VS> VS> pool alloc free read write read write
VS> VS> ---------- ----- ----- ----- ----- ----- -----
VS> VS> disk1 7,45T 8,86T 546 1,49K 16,4M 13,4M
VS> VS> disk1 7,45T 8,86T 272 3,91K 11,7M 27,4M
VS> VS> disk1 7,45T 8,86T 344 2,94K 7,26M 25,2M
VS> VS> disk1 7,45T 8,86T 224 2,02K 9,91M 21,8M
VS> VS> disk1 7,45T 8,86T 244 2,35K 8,23M 18,4M
VS> VS> disk1 7,45T 8,86T 245 2,54K 6,44M 23,4M
VS> VS> disk1 7,45T 8,86T 114 2,94K 3,28M 13,3M
VS> VS> disk1 7,45T 8,86T 288 4,43K 6,09M 33,5M
VS> VS> disk1 7,45T 8,86T 157 1,26K 2,98M 15,7M
VS> VS> disk1 7,45T 8,86T 94 842 3,07M 13,6M
VS> VS> disk1 7,45T 8,86T 327 1,71K 9,63M 8,21M
VS> VS> disk1 7,45T 8,86T 237 1,81K 5,73M 29,3M
VS> VS> disk1 7,45T 8,86T 247 3,47K 5,17M 29,6M
VS> VS> disk1 7,45T 8,86T 165 2,37K 3,22M 16,7M
VS> VS> disk1 7,45T 8,86T 155 3,23K 3,27M 23,9M
VS> VS>
VS> VS> Strange as timeout seted up to 10sec's.
VS> VS>
VS> VS> What intresting - after reboot system work fine for some time, at last while ARC not become 80G size.
VS> VS> Low limit for arc is 40gb, strange but old system can take memory from arc eg like this
VS> VS>
VS> VS>
VS> VS> Mem: 32G Active, 8797M Inact, 78G Wired, 2370M Cache, 209M Buf, 3977M Free
VS> VS> ARC: 43G Total, 2204M MFU, 28G MRU, 135M Anon, 7898M Header, 5301M Other
VS> VS>
VS> VS> On new ARC getting to it max allowed size.
VS> VS>
VS> VS> So for now question is, what it can be, what we can try to improve system perfomance and so on?
VS> VS>
VS> VS>
VS> VS>
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