Subject: Re: unified buffers and responsibility
To: Wojciech Puchar <wojtek@chylonia.3miasto.net>
From: Manuel Bouyer <bouyer@antioche.eu.org>
List: tech-kern
Date: 06/12/2002 22:03:19
On Wed, Jun 12, 2002 at 07:46:50PM +0000, Wojciech Puchar wrote:
> cp <500MB file> otherfile
> 
> no delayed reactions in everything?

I didn't experience it. I tried with your settings, I also have 128M RAM.
However I did notice a strange thing:
for various reasons on both systems I tested,, the copy goes from/to
a different disk than the system disk. While I do the copy,
'systat vm' also shows some activity on the system disk, although
it's not swap:
   14 users    Load  4.45  3.52  2.47                  Wed Jun 12 22:00:12

          memory totals (in KB)             PAGING   SWAPPING      Interrupts
         real   virtual    free             in  out   in  out       530 total
Active  61216     74140     796     ops                             100 irq0
All    123456    136380  134028     pages                             5 irq1
                                                                        irq4
Proc:r  d  s  w    Csw   Trp   Sys  Int  Sof   Flt        forks     178 irq9
        3 15       513   529   405  559  249   401        fkppw      11 irq10
                                                          fksvm         irq11
  11.4% Sy   1.2% Us   0.0% Ni   1.8% In  85.6% Id        pwait     180 irq12
|    |    |    |    |    |    |    |    |    |    |    38 relck      56 irq14
======%                                                38 rlkok         irq15
                                                          noram
Namei         Sys-cache     Proc-cache                  1 ndcpy
    Calls     hits    %     hits     %                    fltcp
       47       42   89        2     4                 13 zfod
                                                          cow
Discs  wd2  wd3  wd4  wd5  wd0  cd0  sd0 raid          64 fmin
seeks                                                  85 ftarg
xfers  179       178        56             80        7677 itarg
Kbyte 3580      4014       688           5066          75 wired
%busy 85.6      97.6      36.8          100.0             pdfre

The cp goes from/to raid which is on wd2/wd4; wd0 is the system
disk. Are you doing the cp from/to the same disk as the system
disk ?

What could cause this activity on wd0 ?

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
--