List, Kevin, Since this merge : commit 1f8bcac09af61e58c5121aa0a932190700ad554d Merge: cb4c254 1042ec9 Author: Anthony Liguori <aligu...@us.ibm.com> Date: Mon Apr 23 14:27:04 2012 -0500
Merge remote-tracking branch 'kwolf/for-anthony' into staging * kwolf/for-anthony: (38 commits) qemu-iotests: Fix test 031 for qcow2 v3 support qemu-iotests: Add -o and make v3 the default for qcow2 qcow2: Zero write support qemu-iotests: Test backing file COW with zero clusters qemu-iotests: add a simple test for write_zeroes qcow2: Support for feature table header extension qcow2: Support reading zero clusters qcow2: Version 3 images qcow2: Ignore reserved bits in check_refcounts qcow2: Ignore reserved bits in refcount table entries qcow2: Simplify count_cow_clusters qcow2: Refactor qcow2_free_any_clusters qcow2: Ignore reserved bits in L1/L2 entries qcow2: Fail write_compressed when overwriting data qcow2: Ignore reserved bits in count_contiguous_clusters() qcow2: Ignore reserved bits in get_cluster_offset qcow2: Save disk size in snapshot header Specification for qcow2 version 3 qcow2: Fix refcount block allocation during qcow2_alloc_cluster_at() iotests: Resolve test failures caused by hostname ... I am seeing some weirdness when using iscsi. I have isolated it to this particular commit, but since it is 3900 lines in sinze I have not yet found the exact change that triggers this particular behaviour. It shows up when using an iscsi device to boot from, where when during the bios boot and later grub boot almost all I/O has a pause of 55ms between them. During boot the bios and later grub will read a lot of data, primarily sequentially and one single block at a time. After these changes were applied there is now an approximate 55ms delay between all these I/O, causing the boot process to become very slow. I have not yet found the exact part of this big patch that cause this slowdown, but will continue investigating. I am posting this here in case someone has any idea or if 55ms rings any bells. regards ronnie sahlberg