Re: fork performance

[Lloyd Parkes <lloyd%must-have-coffee.gen.nz@localhost>]

Early yesterday I decided to gather more data and run some experiments because 
I had found that dump displays elapsed time in system calls (which ktruss 
doesn't do) and it looked like fcntl(2) was taking much more time than fork(2). 
I compiled up a copy of cvs from pkgsrc with the cvs flow control option 
disabled (which appeared to be where the fcntl(2) calls were coming from) and 
the problem went away. I recompiled cvs with the flow control enabled so that I 
would have a proper test and the problem stayed away.

Further testing shows me that the problem is related to some different between 
cvs 1.12.13 and cvs 1.11.23. The answer to my problem is fairly obvious, use 
cvs 1.11.23. I have taken 30 second ktrace from cvs 1.12.13 that shows fork 
taking a quarter of a second every time. This was after cvs had been running 
for about 12 hours on this task and it didn't occur to me to get a copy of its 
memory map before I killed it.

Thanks for the help,
Lloyd