Non re-entrant code faster?

[Mike Anderson]

I just read in the November/December issue of CommUNIXations
an article on page 14 about an application-level implementation
of an OLTP system called Tuxedo.

The article says that "...servers are single-threaded and not
re-entrant. Thus, there is no system support for maintaining
'state information' although an application may provide this
support..."

I presume that this is done for faster performance but I am
not sure why it would be faster. Would someone explain this?

Also, what is meant by "single-threaded"? Aren't all
individual processes single-threaded (multiple processes
may take separate paths through the text image)?

And what "state information" would the system maintain for
re-entrant code that would be useful to an application?
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Thanks,
Mike Anderson
..!uunet!sean!mka