Re: Confusion regarding the use of OP_TIMEOUT

[Alex O'Brien <alex@emobrien.com>]

On 5/20/21 5:51 AM, Drew DeVault wrote:
> Hi folks! I'm trying to use IO_TIMEOUT to insert a pause in the middle
> of my SQ. I set the off (desired number of events to wait for) to zero,
> which according to the docs just makes it behave like a timer.
> 
> Essentially, I want the following:
> 
> [operations...]
> OP_TIMEOUT
> [operations...]
> 
> To be well-ordered, so that the second batch executes after the first.
> To accomplish this, I've tried to submit the first operation of the
> second batch with IO_DRAIN, which causes the CQE to be delayed, but
> ultimately it fails with EINTR instead of just waiting to execute.
> 
> I understand that the primary motivator for OP_TIMEOUT is to provide a
> timeout functionality for other CQEs. Is my use-case not accomodated by
> io_uring?
> 

Have you tried setting `IO_DRAIN` on the timeout operation itself?

-- 
- Alex O'Brien
<alex@emobrien.com>