Re: [PATCH v5 0/5] qcow2: async handling of fragmented io

[Max Reitz <mreitz@redhat.com>]

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On 16.09.19 19:53, Vladimir Sementsov-Ogievskiy wrote:
> Hi all!
> 
> Here is an asynchronous scheme for handling fragmented qcow2
> reads and writes. Both qcow2 read and write functions loops through
> sequential portions of data. The series aim it to parallelize these
> loops iterations.
> It improves performance for fragmented qcow2 images, I've tested it
> as described below.

Thanks again, applied to my block branch:

https://git.xanclic.moe/XanClic/qemu/commits/branch/block

> v5: fix 026 and rebase on Max's block branch [perf results not updated]:
> 
> 01: new, prepare 026 to not fail
> 03: - drop read_encrypted blkdbg event [Kevin]
>     - assert((x & (BDRV_SECTOR_SIZE - 1)) == 0) -> assert(QEMU_IS_ALIGNED(x, BDRV_SECTOR_SIZE)) [rebase]
>     - full host offset in argument of qcow2_co_decrypt [rebase]
> 04: - substitute remaining qcow2_co_do_pwritev by qcow2_co_pwritev_task in comment [Max]
>     - full host offset in argument of qcow2_co_encrypt [rebase]
> 05: - Now patch don't affect 026 iotest, so its output is not changed
> 
> Rebase changes seems trivial, so, I've kept r-b marks.

(For the record, I didn’t consider them trivial, or I’d’ve applied
Maxim’s series on top of yours.  I consider a conflict to be trivially
resolvable only if there is only one way of doing it; but when I
resolved the conflicts myself, I resolved the one in patch 3 differently
from you – I added an offset_in_cluster variable to
qcow2_co_preadv_encrypted().  Sure, it’s still simple and the difference
is minor, but that was exactly where I thought that I can’t consider
this trivial.)

Max


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