Forgot to add: On localhost I don't have any issues, it happens when writing to somewhere else.
Am Sonntag, 23. Februar 2014 23:34:39 UTC+1 schrieb Guido van Rossum: > > I haven't been able to repro this using the test you attached to issue > 153. But I don't have another machine available, I've only tried localhost > on OSX (10.9) and from that same box to a local virtual machine running > Ubunu. The receiving end just throws away the data -- is that your test > setup too? I used "while 1: s.recv(10000); n += 1" in an interactive Python > shell. > > I do see packet loss (just counting packets received and packets sent) but > no exceptions nor does pause_writing() ever get called. From putting some > print()s in the code it looks like the sendto() operation always > immediately succeeds. > > The errno has a name: errno.ENOBUFS -- it's 55 on OSX, but 105 on Ubuntu. > > Perhaps you can elaborate on your test setup? > > > On Sun, Feb 23, 2014 at 11:29 AM, Christopher Probst < > foxnet.d...@googlemail.com <javascript:>> wrote: > >> Ok, I tried it now with 180 bytes packet and it does not occur, I guess >> that my lan connection(gigabit) is too fast that those packets get queued >> up. Or OSX decide whether or not to queue those packets based on the size. >> But this seems to be heavily os dependent . >> >> Am Sonntag, 23. Februar 2014 20:12:46 UTC+1 schrieb Guido van Rossum: >>> >>> Have you tried reducing the write buffer size? >>> On Feb 23, 2014 10:41 AM, "Christopher Probst" <foxnet.d...@googlemail. >>> com> wrote: >>> >>>> I saw this in the official 3.4rc1 doc. >>>> >>>> The doc says, that flow-control callbacks are valid for Protocols and >>>> SubprocessProtocols, but DatagramProtocol is not specified. >>>> >>>> Though I'm happy that Datagram control flow is officially supported I >>>> have now an other problem which is directly connected with this issue. >>>> Using OSX10.9.1 and python 3.3 sending a lot of udp packets actually >>>> does not cause the flow-control to be activated but throws an OSError(55 >>>> *No >>>> buffer space available)* . >>>> >>>> After googling around for hours I found out that this is a BSD(probably >>>> OS X only) thing. On linux the control-flow works as expected. >>>> >>>> I listed an issue for this in your tulip repo: >>>> Issue 153 <https://code.google.com/p/tulip/issues/detail?id=153> >>>> >>>> I think that this is really not a python bug, but the way BSD/OSX >>>> handles too much udp packets (the socket sdnbuf option is kind of ignored >>>> by OSX). I've read that windows actually handles udp overload in a >>>> similiar >>>> way as BSD does. Though i don't have a windows machine this should >>>> probably >>>> be tested to confirm or disprove this issue. >>>> >>>> PS: >>>> 18.5.3.2.5. Flow control >>>> callbacks<http://docs.python.org/3.4/library/asyncio-protocol.html#flow-control-callbacks> >>>> >>>> >>>> These callbacks may be called on >>>> Protocol<http://docs.python.org/3.4/library/asyncio-protocol.html#asyncio.Protocol> >>>> and >>>> SubprocessProtocol<http://docs.python.org/3.4/library/asyncio-protocol.html#asyncio.SubprocessProtocol> >>>> instances: >>>> BaseProtocol.pause_writing()<http://docs.python.org/3.4/library/asyncio-protocol.html#asyncio.BaseProtocol.pause_writing> >>>> >>>> >>>> Called when the transport’s buffer goes over the high-water mark. >>>> BaseProtocol.resume_writing()<http://docs.python.org/3.4/library/asyncio-protocol.html#asyncio.BaseProtocol.resume_writing> >>>> >>>> >>>> Called when the transport’s buffer drains below the low-water mark. >>>> >>>> >>>> >>>> >>>> Am Sonntag, 23. Februar 2014 18:56:42 UTC+1 schrieb Guido van Rossum: >>>>> >>>>> This looks like a bug in the docs; the intention is that datagram >>>>> protocols also support flow control. Where does it say so in the docs? Is >>>>> it the PEP or the CPython Doc tree? >>>>> >>>>> >>>>> On Sat, Feb 22, 2014 at 5:12 PM, Christopher Probst < >>>>> foxnet.d...@googlemail.com> wrote: >>>>> >>>>>> Hi, >>>>>> >>>>>> after looking into the implementation I saw that, for instance, _ >>>>>> SelectorDatagramTransport calls _maybe_pause_protocol and it's >>>>>> counterpart, but the doc says that only Protocol and SubprocessProtocol >>>>>> has >>>>>> flow-control support and DatagramProtocol does not. >>>>>> >>>>>> I know that udp flow-control is not the same as tcp flow-control, but >>>>>> I'm concerned about filling up the internal buffer when writing a lot of >>>>>> datagrams. If this is not supported, I would argue that the udp >>>>>> support is pretty much broken for data intense application because how >>>>>> would the writer know when the internal buffer (and/or kernel level >>>>>> buffer) >>>>>> are full ? >>>>>> >>>>>> So, is the doc just not up-to-date or is it an implementation detail >>>>>> of tulip ? >>>>>> >>>>>> And other question that came up: Are there any plans for coroutine >>>>>> methods for udp (like StreamWriter/Reader for TCP) ? >>>>>> >>>>>> Also, are there any "dirty" corners somebody heavily working with udp >>>>>> have to know ? I'm implementing reliable udp and I would like to use the >>>>>> coroutine style instead of callbacks. >>>>>> >>>>>> >>>>>> Regards, >>>>>> Chris >>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> --Guido van Rossum (python.org/~guido) >>>>> >>>> > > > -- > --Guido van Rossum (python.org/~guido) >
