Author: Theo E. Schlossnagle Date: To: Richard Welty CC: exim-users New-Topics: [Exim] Re: Dynamically Loadable Modules Subject: Re: Dynamically Loadable Modules (was Re: [Exim] Is Exin SNMP Aware? )
Richard Welty wrote: >>That's probably the biggest head-ache. I'm not sure of many systems
>>where dynamic linking, on any level, could be considered "cheap" when
>>done incredibly frequently, say on a dedicated mail server.
>
> i have to vote against the whole idea; it would be way too expensive
> in a busy mail server.
Where is your emprical evidence for this. I don't buy it. Dynamic linking
happens all the time on my busy systems and things fly. Sounds like your
dynamic linker is broken.
Besides, most modules loaded into exim would be very small. So you are only
looking at a mmap() and a symbol table verification. There are probably only
a handful of symbols in one of these modules, so this overhead is TINY.
I would rather load 100 modules than call {fsync,fsyncdata} just once on my
busy systems. It the battle for speed, choose your bottleneck battles wisely.
--
Theo Schlossnagle
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