Re: [Nbd] another?

[Wouter Verhelst <w@...112...>]

On Fri, Sep 16, 2011 at 11:14:54AM +0100, Alex Bligh wrote:
> 
> 
> --On 16 September 2011 10:34:46 +0200 Wouter Verhelst <w@...112...> wrote:
> 
> > Of course, relying on TCP to do this does make it possible that both
> > the client and the server are writing to the socket at the same time
> > when one of them needs to do a read first before things can go on,
> > thereby deadlocking the connection. This is what happens with the
> > integrityhuge test on some platforms, which is why I've disabled it for
> > now
> 
> Mmm.... if a server can't cope with client and server both writing
> to the socket at the same time, doesn't that illustrate a bug on the
> server?

Absolutely.

> IE isn't the correct thing to do to fix the bug, not disable the test?

Yes, but fixing this bug is non-trivial. Mean time, I have a choice
between continuing to support a version which works most of the time, or
not supporting any version for a long time until I've got a working
version that can cope with this deadlock.

> Is this some form of deadlock you are talking about?

Yes; both sides of the conversation are waiting on the other to read.
It'll be fixed once one end will be able to read and write
simultaneously, and my multithreaded implementation is capable of doing
so. It just needs to actually /work/, before I can release it :-)

-- 
The volume of a pizza of thickness a and radius z can be described by
the following formula:

pi zz a