Messages in this thread | | | From | Hans-Peter Jansen <> | Subject | latency problems with 2.6.24.3 and before (probably xfs related) | Date | Sat, 1 Mar 2008 12:19:29 +0100 |
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Hi,
I'm suffering from latency problems on a openSUSE 10.2 server with kernel 2.6.24.3. To get gripe on it, I finally got around installing latencytop from git, and that output pretty much reflects the pathologic situation:
Process cupsd (4917) xlog_state_sync _xfs_log_force xfs_alloc_search_bu2480.0 msec 59.2 %s_alloc_vextent xfs_bmap_btalloc xfs_bmap_al vn_iowait xfs_setattr xfs_vn_setattr notify_change1957.5 msec 26.8 %_namei do_filp_open do_sys_open sys_open sys xfs_buf_lock xfs_getsb xfs_trans_getsb xfs_trans_a1269.6 msec 8.0 %commit xfs_itruncate_finish xfs_setattr xfs_ xfs_buf_lock xfs_getsb xfs_trans_getsb xfs_trans_a968.8 msec 6.1 %_commit xfs_iomap_write_allocate xfs_iomap xf s_bmap xfs_map_blocks xfs_page_state_convert xfs_vm_writepage __writepage
Process svn (16210) sync_page __lock_page do_generic_mapping_read gene2289.2 msec 55.8 % xfs_file_aio_read do_sync_read vfs_read sys xfs_buf_iowait xfs_buf_iostart xfs_buf_read_flags 1714.8 msec 27.2 %do_buf xfs_da_read_buf xfs_dir2_block_lookup xfs_buf_iowait xfs_buf_iostart xfs_buf_read_flags 1175.6 msec 15.2 %bp xfs_iread xfs_iget_core xfs_iget xfs_dir_ xfs_buf_lock xfs_getsb xfs_trans_getsb xfs_trans_a191.4 msec 1.7 %_commit xfs_create xfs_vn_mknod xfs_vn_create vfs_create open_namei do_filp_open do_sys_open
Process find (15502) xfs_buf_iowait xfs_buf_iostart xfs_buf_read_flags 1468.8 msec 43.8 %bp xfs_iread xfs_iget_core xfs_iget xfs_dir_ xfs_buf_iowait xfs_buf_iostart xfs_buf_read_flags 1070.4 msec 56.2 %do_buf xfs_da_read_buf xfs_dir2_block_getden ts xfs_readdir xfs_file_readdir vfs_readdir sys_getdents64 sysenter_past_esp
Okay, that doesn't look funny in any way. Up to 2,5 sec latency is way too much, given the equipment in play: Tyan S2882-D, 2 * AMD Opteron 265 DC, 4GB RAM, Areca ARC-1130 12-Port PCI-X to SATA RAID Controller, main system installed on 4 * Hitachi 500GB SATA drives in a RAID 5 setup. The kernel config is based on the default SUSE setup for i386 with pae extension, compiled with HZ 250, running with SCHED_MINTIMESLICE="10000", SCHED_MAXTIMESLICE="100000".
It looks like it's xfs related. I suspect, cupsd mostly operates on /var, which has it's own partition:
meta-data=/dev/sda6 isize=256 agcount=16, agsize=2457567 blks = sectsz=512 attr=0 data = bsize=4096 blocks=39321072, imaxpct=25 = sunit=0 swidth=0 blks, unwritten=1 naming =version 2 bsize=4096 log =internal bsize=4096 blocks=19199, version=1 = sectsz=512 sunit=0 blks, lazy-count=0 realtime =none extsz=65536 blocks=0, rtextents=0
Any ideas, what's wrong here?
Pete
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