FYI: dccproc vs dccifd

[Ugo Bellavance]

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Here is a discussion I has on the DCC mailing list with DCC's author:

 > long time if there was a clear-cut advantage to run dccifd instead of
 > dccproc on a mail server.  In my case, MailScanner calls SpamAssassin,
 > which in turn calls DCC.  I usually use DCCifd on the servers I
 > maintain, but I haven't done any real performance tests.  I know that > a
 > daemon like DCCifd is usually faster than a single process because it 
 >  is
 > always in memory, but I've been told that since dccproc is called very
 > often, the process of paging in/out shouldn't be very slow.  Comments?

dccproc involves a fork() and exec() and then sending the message through
a pipe to the child process and receiving the answer.
dccifd need only send the message over UNIX domain socket to a daemon
and receiving the answer.

Dccproc must open, validate, and mmap() the whiteclnt and whiteclnt.dccw
files, while dccifd caches open files and mmap() regions.
Dccproc also creates creates a socket to talk to the DCC server while
dccifd caches open sockets.

I must admit that I've been too lazy to do obvious tests.

Vernon Schryver

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Ugo

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