numbers don't lie ...

[Dmitry Morozovsky]

On Tue, 19 Sep 2006, Kris Kennaway wrote:

KK> > OF> Because buildworld is I/O-bound on systems with sufficiently
KK> > OF> fast processors.
KK> > OF> 
KK> > OF> Try putting the contents of /usr/src into a RAM disk and
KK> > OF> repeat the benchmark.  The numbers might look a little
KK> > OF> different then.  Of course, you should have sufficient RAM
KK> > OF> in the machines -- If they're going to swap to the disks,
KK> > OF> your benchmark won't be happy.
KK> > OF> 
KK> > OF> I think putting /usr/obj onto a RAM disk is _not_ necessary
KK> > OF> because of soft-updates, so the processes shouldn't block
KK> > OF> on writes.
KK> > 
KK> > My experiments show that if you have enough memory to host radmdrive for 
KK> > /usr/src you'd better leave it for caching - there were no statistically
KK> > meaningful performance difference, at least on machines with 1G+ RAM.
KK> 
KK> Really?  My measurements show the opposite (on a system with 16GB of
KK> RAM).

My last test on amd64/dualcore with 4G of RAM and -j4 shows 
(buildworld+buildkernel):

==> /tmp/buildlog <==
     1996.45 real      3032.94 user       624.83 sys
Script done on Tue Sep 19 14:44:54 2006

==> /tmp/buildlog.md <==
     1957.45 real      3033.93 user       585.78 sys
Script done on Tue Sep 19 15:20:42 2006

Second one was with 512M/4k/512 swap-backed md, the former with /usr/src on the 
gmirror'ed pair of SATAs.



Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
------------------------------------------------------------------------
*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck at rinet.ru ***
------------------------------------------------------------------------