This series fixes QCOW locking issues and implements delayed metadata writeout. This improves performance of writeout to QCOW2 images that don't have clusters and L2 tables allocated on-disk. I tested the series by running mount -t ext4 /dev/vdb /mnt dd if=/dev/zero of=/mnt/tmp in the guest multiple times for fresly generated QCOW2 image: dd if=/dev/zero of=fs.ext4 bs=1024k count=512 && mkfs.ext4 -F fs.ext4 && qemu-img convert -O qcow2 fs.ext4 fs.qcow2 which causes worst-case behavior for the current code. Before: [ seekwatcher: http://userweb.kernel.org/~penberg/kvm-qcow-delayed/kvm-qcow2-master.png ] 511229952 bytes (511 MB) copied, 19.906 s, 25.7 MB/s 511229952 bytes (511 MB) copied, 20.3168 s, 25.2 MB/s 511229952 bytes (511 MB) copied, 20.8078 s, 24.6 MB/s 511229952 bytes (511 MB) copied, 21.0889 s, 24.2 MB/s 511229952 bytes (511 MB) copied, 20.7833 s, 24.6 MB/s 511229952 bytes (511 MB) copied, 20.7536 s, 24.6 MB/s 511229952 bytes (511 MB) copied, 20.0312 s, 25.5 MB/s After: [ seekwatcher: http://userweb.kernel.org/~penberg/kvm-qcow-delayed/kvm-qcow2-delayed.png ] 511229952 bytes (511 MB) copied, 7.68312 s, 66.5 MB/s 511229952 bytes (511 MB) copied, 7.54065 s, 67.8 MB/s 511229952 bytes (511 MB) copied, 9.34749 s, 54.7 MB/s 511229952 bytes (511 MB) copied, 9.2421 s, 55.3 MB/s 511229952 bytes (511 MB) copied, 9.9364 s, 51.5 MB/s 511229952 bytes (511 MB) copied, 10.0337 s, 51.0 MB/s 511229952 bytes (511 MB) copied, 9.39502 s, 54.4 MB/s For comparison, the results for raw ext4 images are as follows: [ seekwatcher: http://userweb.kernel.org/~penberg/kvm-qcow-delayed/kvm-raw.png ] 511229952 bytes (511 MB) copied, 8.75403 s, 58.4 MB/s 511229952 bytes (511 MB) copied, 10.3326 s, 49.5 MB/s 511229952 bytes (511 MB) copied, 6.8494 s, 74.6 MB/s 511229952 bytes (511 MB) copied, 9.21538 s, 55.5 MB/s 511229952 bytes (511 MB) copied, 8.52883 s, 59.9 MB/s 511229952 bytes (511 MB) copied, 8.13298 s, 62.9 MB/s 511229952 bytes (511 MB) copied, 5.03801 s, 101 MB/s Pekka Pekka Enberg (9): kvm tools, qcow: Rename struct qcow_l2_cache to struct qcow_l2_table kvm tools, qcow: Use 'struct qcow_l2_table' instead of untyped array kvm tools, qcow: Fix locking issues kvm tools, qcow: Introduce qcow_disk_flush() kvm tools, qcow: Delayed L1 table writeout kvm tools, qcow: Don't fdatasync() L2 table writeout kvm tools, qcow: Use big endian order for L2 table entries kvm tools, qcow: Delayed L2 table writeout kvm tools, qcow: Flush only dirty L2 tables tools/kvm/disk/qcow.c | 248 ++++++++++++++++++++++------------------- tools/kvm/include/kvm/mutex.h | 6 + tools/kvm/include/kvm/qcow.h | 6 +- 3 files changed, 145 insertions(+), 115 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
