search for: latencytop

Hi, we are running a ceph cluster with btrfs as it''s base filesystem (kernel 3.0). At the beginning everything worked very well, but after a few days (2-3) things are getting very slow. When I look at the object store servers I see heavy disk-i/o on the btrfs filesystems (disk utilization is between 60% and 100%). I also did some tracing on the Cepp-Object-Store-Daemon, but I''m

I see Intel has released a new tool. Oh, it requires some patches to the kernel to record latency times. Good thing people don''t mind patching their kernels, eh? So who can write the equivalent latencytop.d the fastest? ;-) http://www.latencytop.org/ -- cburgess at qnx.com

...0 3 0 sda5 dmesg 3630 1 1 0 0 sda5 sleep 3629 1 1 0 0 sda5 I think that is the same problem as in http://marc.info/?l=ceph-devel&m=131158049117139&w=2 I also did a latencytop as Chris recommended in the above thread. Best Regards, martin

...is to create a zpool consisting of a single OCZ Vertex 4 SSD, sharing it as NFS and running iometer on a VM and see how it performs in a "real world" use-case... but that doesn''t necessarily isolate how well it performs as a ZIL. Another thing I found is Brendan Gregg''s latencytop.d dtrace script ( http://www.mail-archive.com/dtrace-discuss at opensolaris.org/msg00934.html), but the examples I''ve seen don''t seem to isolate an individual disk. Are there any other useful scripts, commands or resources I should be aware of? Thanks, Matt -------------- next p...

At our Physics research labs we do a lot with low latency networks. We have been using Centos for over 3 years now and its been great! We would like to tune and optimize our setup by removing unneeded packages -- kernel modules to be specific. I was wondering, how does one measure the speed of the kernel. Is that even possible?

2011/10/26 Sage Weil <sage@newdream.net>: > On Wed, 26 Oct 2011, Christian Brunner wrote: >> >> > Christian, have you tweaked those settings in your ceph.conf?  It would be >> >> > something like ''journal dio = false''.  If not, can you verify that >> >> > directio shows true when the journal is initialized from your osd log?

..., and I''ve always felt booting was very slow, but definitely sure is slow, is starting up Google Chrome: encrypted ext4: ~20s btrfs: ~2:11s I have tried different things to find out exactly what is the issue, but haven''t quite found it yet. Here''s some stuff I got from latencytop, not sure if would be helpful: 4969.1ms sys_mmap_pgoff syscall_call (chrome) 1139.9ms sync_page sync_page_killable __lock_page_killable generic_file_aio_read do_sync_read vfs_read sys_read sysenter_do_call (chrome) 431.9ms sync_page wait_on_page_bit read_extent_buffer_pages btree_read_extent_buf...

Hi list, I don''t trust theoretical benchmarks that much and prefer "real-life benchs" on the occasion, so here''s mine: Given 4 laptops, the most powerful of which was running BTRFS and the others ext3 or ext4, all machines running Ubuntu 11.04 Natty 32-bit with a stock Ubuntu 2.6.38-11 kernel, all machines were given the following FS-intensive task : - Upgrade