Am 13.02.26 um 3:33 PM schrieb Jens Axboe:
> Hi,
> 
> Patch 1 here is the real meat of this, patch 2 is just a slight
> improvement. For patch 1, it can literally yield a 50-80x improvement
> on the io_uring side for idle systems, where ppoll() ends up sleeping
> for 500 msec while there's IO to submit! I noticed this running the
> io_uring regression tests in a vm, where I use a variety of block
> devices for some of the tests. They would often randomly time out on
> AHCI devices, while running them on a virtio-blk or nvme device would
> finish in one second or so. I then wrote a reproducer to try and grok
> this and had claude dive into this, which helped me better grasp the
> various event loops.
> 
> Please take a look and tell me what you think. Some variant of patch 1
> should definitely be considered, but let me know if this is the right
> approach. I can easily test anything.
> 
> Also note - this seems to trigger more easily or consistently on
> aarch64, which is where I run most of my local/immediate testing.
> 
>  util/fdmon-io_uring.c | 22 +++++++++++++++++++++-
>  1 file changed, 21 insertions(+), 1 deletion(-)
> 

CC-ing qemu-stable since this affects the 10.2 branch. The fixes are
already applied to master as

2ae361ef1d aio-posix: notify main loop when SQEs are queued
961fcc0f22 fdmon-io_uring: check CQ ring directly in gsource_check

Best Regards,
Fiona


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