benchmark: fix net/dgram.js infinite loop

[yosuke-furukawa]

benchmark script is not finished. net/dgram.js has infinite loop.

[mscdex]

I saw this the other day too, but I'm not sure what impact setImmediate() brings.

[bnoordhuis]

I think there are two things going on here:

1. the benchmark hasn't been updated after changes to the dgram binding interface
2. using setImmediate() this way is an accidental fix; the return value from setImmediate() makes the socket.send() call compatible-ish with the new interface again

EDIT: Sorry, scratch that; I thought this benchmark was using the binding layer directly.

[yosuke-furukawa]

if this bug is solved, all benchmark tests work fine.

I would like to ask a question. this callback seems to be called synchronously, is this a right behavior?

IMO, UDP does not check reaching the target, so the behavior looks fine.

[bnoordhuis]

this callback seems to be called synchronously, is this a right behavior?

If that is what happens, then no, that would definitely be the wrong behavior. I don't think it's that, though. I did a quick check and it seems the callback is just never called. Will investigate.

[bnoordhuis]

Okay, perhaps it does get called synchronously somehow.

[yosuke-furukawa]

I investigate this issue using git bisect.

As a result, I suspect this commit (e49429e) occurs this issue ( deps: update libuv to v0.11.28 e49429e ).

[yosuke-furukawa]

According to libuv CHANGELOG, I can find a commit " unix: try to write immediately in uv_udp_send libuv/libuv@4189122".

@bnoordhuis I guess this is the reason why socket.send callback is called synchronously. How do I fix this script? setImmediate is OK?

[yosuke-furukawa]

ping @bnoordhuis ?

[vkurchatkin]

shouldn't it be like setImmediate.bind(null, onsend) ?

[bnoordhuis]

@yosuke-furukawa I appreciate the fix for the test, but if callbacks are really getting called synchronously now, that will have to be addressed. It violates the 'callbacks are always asynchronous' contract.

[vkurchatkin]

Closing. This PR doesn't seem to fix anything