On Fri, 20 Feb 2009, erik quanstrom wrote:
On Fri Feb 20 11:18:41 EST 2009, urie...@gmail.com wrote:
One of the main costs of dynamic linking is making fork much slower.
Even on linux statically linked binaries fork a few magnitude orders
faster than dynamically linked ones.
The main source of anti-fork FUD turns out to be the alleged
'solution' to a problem that didn't exist until the geniuses at Sun
decided dynamic linking was such a wonderful idea.
very generally, i agree with the direction of your
post. but i do remember things a bit differently.
iirc, this went the other way 'round. fork itself
was very expensive on sun hardware in the early
90s if one had some memory mapped. sun mmus
had issues. i benchmarked a vax 11/780 vs a sun
670mp. the 4x50mhz 670mp was scheduled to replace the
1x5mhz (?) vaxen. the vax forked maybe 10x faster when no
memory was allocated. however, when a moderate
amount of memory was allocated, the vax pounded
the sun by many (3, i think) of magnitude.
about 5 years ago i took a class on performance tuning Solaris.
The instructor claimed that fork was expensive because accounting is never
really turned off, just piped to /dev/null. there is no accounting overhead
for threads.
I never bothered to verify this, but now that this comes up, I'd tempted.
- erik
