initial writes with soft-updates

[Jan Pechanec]

	hello all,

	could you please shed some light on this situation? When I create 
many files at once with soft updates enabled, I can see some initial writes 
(8 in this example) during the 1st second of the operation. After that, it's 
silent till the next sync() - which is expected.

	the whole operation takes 4-5 seconds on my not brand-new 500MHz 
machine so I just cannot understand those first writes. I know how soft 
updates work and that's why I can't understand it. The system is 
5.3-RELEASE-p23, 128 MB RAM with 70 MB free at least, load is nearly zero - 
just the test running (load averages:  0.15, 0.03, 0.01).

	I don't think it's about version, I have to be missing something 
about soft updates, just don't know what it is. When I try it with just a 
few files (< 10), there is no immediate write. I'm looking into soft updates 
chapter of McKusick's book on FreeBSD right now and cannot find an answer 
there either.

# time for i in `jot 1000`; do touch file-$i; done

real    0m4.676s
user    0m0.677s
sys     0m3.931s


# iostat -c 100 -d ad0

 14.25   8  0.11 
  0.00   0  0.00 
  0.00   0  0.00 
  0.00   0  0.00 
  0.00   0  0.00 
  0.00   0  0.00 
  0.00   0  0.00 
  0.00   0  0.00 


	please CC: on me, I'm not already a member of this list.

	thank you, j.

-- 
Jan Pechanec <jp (at) devnull (dot) cz>
http://www.devnull.cz