[Python-Dev] Synchronous and Asynchronous servers in the standard library

["Martin v. Löwis"]

Andrew Bennetts wrote:
> One such list is here:
>     http://mail.zope.org/pipermail/zope3-dev/2002-October/003235.html

I fail to see any of these as problematic:

1. invokes readable/writable in each round, thereby not preserving
    state; presumably ok for select and poll, but bad (wasting
    performance for kqueue).
    I can't see this as a problem: asyncore does use select/poll,
    not kqueue. In doing so, it first processes all ready file
    descriptors before going to the next round, so in the next
    round, it needs to check all dispatchers again.
    There seems to be an implicit assertion that anything that uses
    select/poll must be evil, and the only true API is kqueue.
    I can't claim to understand the rationale for introducing
    kqueue in the first place, but if it is to improve performance,
    then I expect that any performance gained in kqueue over
    select goes away by using Python (e.g. adding an indirection
    in dispatching is probably more expensive than what kqueue
    would have saved).

2. ties together protocol and transport. So what? I don't
    want to use SMTP over UDP, or X.25. TCP, possibly together
    with TLS, is just fine.

3. tied to sockets. Again: so what? I can't follow the assertion
    that you cannot use pyOpenSSL because of that, but then,
    I haven't used pyOpenSSL. The only possible interpretation
    is that pyOpenSSL does not expose "raw" (pollable) socket
    objects, which would really sound like a limitation in
    pyOpenSSL, not in asyncore.

a. Cannot use NT I/O completion ports. Again, what's wrong
    with select? Performance? I'd really like to see a Python
    application where the speed gain from IOCP is significant
    compared to using select. The limit of 64 sockets is serious,
    but Python bumps it to 512.

b. cannot do the the TCP transfer code in the C networking
    core. I don't really understand that point. What is the
    TCP transfer code?

Regards,
Martin