Re: [Qemu-devel] QEMU event loop optimizations

[Paolo Bonzini]

On 02/04/19 18:18, Kevin Wolf wrote:
> Am 26.03.2019 um 15:11 hat Paolo Bonzini geschrieben:
>> - but actually (and a precursor to using IOCB_CMD_POLL) it should be
>> possible to have just one LinuxAioState per AioContext, and then
>> it can simply share the AioContext's EventNotifier.  This removes
>> the need to do the event_notifier_test_and_clear in linux-aio.c.
> 
> Isn't having only one LinuxAioState per AioContext what we already do?
> See aio_get_linux_aio().

And I should have known that:

    commit 0187f5c9cb172771ba85c66e3bf61f8cde6d6561
    Author: Paolo Bonzini <address@hidden>
    Date:   Mon Jul 4 18:33:20 2016 +0200

    linux-aio: share one LinuxAioState within an AioContext

    This has better performance because it executes fewer system calls
    and does not use a bottom half per disk.

    Originally proposed by Ming Lei.

The second point, which is to share the AioContext's EventNotifier,
still stands.

Paolo