imapd -U in cyrus.conf

[Simon Matter]

> Peter Clark wrote:
>> Hello all,
>>
>> Not really understanding the -U (reuses) flag, is there an advantage to
>> using it? I imagine that there is in some specific instances so I better
>> ask the question differently. When would it be advantageous to use the
>> -U flag in cyrus.conf?
>>
>> ie:
>>   imap          cmd="imapd -U 60" listen="imap" prefork=6
>
> If process creation is expensive on your system, it's good to reuse an
> existing imapd process as many times as possible to avoid the fork()
> overhead.

I was just wondering whether there is a list somewhere on how expensive a
fork() is on different platforms.
I know it should be quite fast on Linux but some Unices make it expensive.
I'm wondering which one are expensive these days.

Regards,
Simon