copying pkgsrc tree around jails on beefy machine - fast on 2nd iteration, a bit slower than first on 3rd iteration

[Matthew Dillon]

:Hello!
:
:	While testing 1.4rc with jails - actually preparing for jails I noticed this:
:
:dk# cd /usr/
:dk# time cp -pr pkgsrc /jails/pgsql81/usr
:0.296u 9.586s 2:09.93 7.5%      59+440k 26099+1175io 90342pf+0w
:dk# time cp -pr pkgsrc /net/jails/oglasi/usr
:0.429u 8.692s 0:48.14 18.9%     61+447k 1816+1175io 7084pf+0w
:dk# time cp -pr pkgsrc /jails/mysql/usr
:0.445u 14.146s 2:12.14 11.0%    56+415k 1889+1176io 80390pf+0w
:dk# du -sk /usr/pkgsrc
:357080  /usr/pkgsrc
:
:
:Basically I was copying 357MB pkgsrc dir from master to jails in a row. I manually re-edited destination each time. All 
:in a row, but you can see that 3rd copy did not benefit at all from first two copies. Since this machine is waiting for 
:those jails to actually do something I was under impression that 4GB RAM that this machine sees will benefit a lot in 
:copying - something like in 2nd case, but I was surprised that caching did not help at all in third case even though 
:things were being copied in a row - usually few seconds apart. Isn't DFly one of so called lazy-swappers where things do 
:not go out of memory if memory needs for programs are low?
:
:Toma¾

    This is likely just the vnode cache getting blown out.  /usr/pkgsrc has
    over 100,000 files and directories in it.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>