On 3/15/24 16:25, Jens Axboe wrote:
On 3/15/24 10:23 AM, Pavel Begunkov wrote:
On 3/15/24 16:20, Jens Axboe wrote:
On 3/15/24 9:30 AM, Pavel Begunkov wrote:
io_post_aux_cqe(), which is used for multishot requests, delays
completions by putting CQEs into a temporary array for the purpose
completion lock/flush batching.
DEFER_TASKRUN doesn't need any locking, so for it we can put completions
directly into the CQ and defer post completion handling with a flag.
That leaves !DEFER_TASKRUN, which is not that interesting / hot for
multishot requests, so have conditional locking with deferred flush
for them.
This breaks the read-mshot test case, looking into what is going on
there.
I forgot to mention, yes it does, the test makes odd assumptions about
overflows, IIRC it expects that the kernel allows one and only one aux
CQE to be overflown. Let me double check
Yeah this is very possible, the overflow checking could be broken in
there. I'll poke at it and report back.
test() {
if (!(cqe->flags & IORING_CQE_F_MORE)) {
/* we expect this on overflow */
if (overflow && (i - 1 == NR_OVERFLOW))
break;
fprintf(stderr, "no more cqes\n");
return 1;
}
...
}
It's this chunk. I think I silenced it with
s/i - 1 == NR_OVERFLOW/i == NR_OVERFLOW/
but it should probably be i >= NR_OVERFLOW or so
--
Pavel Begunkov
