Hello,

Trying to understand the ZFS IO scheduler, because of the async nature it is 
not very apparent, can someone give a short explanation for each of these stack 
traces and for  their frequency

this is the command

dd if=/dev/zero of=/test/test1/trash count=1 bs=1024k;sync

no other IO is happening to the test pool. OS is on a zfs pool (rpool)


I don't see any zio_vdev_io_start in any of the function stacks, any idea why?

dtrace -n 'io:::start { @a[stack()] = count(); }'

dtrace: description 'io:::start ' matched 6 probes


             genunix`bdev_strategy+0x44
              zfs`vdev_disk_io_start+0x2a8
              zfs`zio_execute+0x74
              genunix`taskq_thread+0x1a4
              unix`thread_start+0x4
               20

              genunix`bdev_strategy+0x44
              zfs`vdev_disk_io_start+0x2a8
              zfs`zio_execute+0x74
              zfs`vdev_queue_io_done+0x84
              zfs`vdev_disk_io_done+0x4
              zfs`zio_execute+0x74
              genunix`taskq_thread+0x1a4
              unix`thread_start+0x4
               31

              genunix`bdev_strategy+0x44
              zfs`vdev_disk_io_start+0x2a8
              zfs`zio_execute+0x74
              zfs`vdev_mirror_io_start+0x1b4
              zfs`zio_execute+0x74
              zfs`vdev_mirror_io_start+0x1b4
              zfs`zio_execute+0x74
              genunix`taskq_thread+0x1a4
              unix`thread_start+0x4
               34

              genunix`bdev_strategy+0x44
              zfs`vdev_disk_io_start+0x2a8
              zfs`zio_execute+0x74
              zfs`vdev_mirror_io_start+0x1b4
              zfs`zio_execute+0x74
              genunix`taskq_thread+0x1a4
              unix`thread_start+0x4
               45

              genunix`bdev_strategy+0x44
              zfs`vdev_disk_io_start+0x2a8
              zfs`zio_execute+0x74
              zfs`vdev_queue_io_done+0x9c
              zfs`vdev_disk_io_done+0x4
              zfs`zio_execute+0x74
              genunix`taskq_thread+0x1a4
              unix`thread_start+0x4
               53
-- 
This message posted from opensolaris.org
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss

Reply via email to