[ale] [On-topic] "wa" number in "top"?

[Michael B. Trausch]

JK wrote:
> 
> Any clues would be appreciated. Really, just knowing
> exactly what "wa" means would be a big help.
> 

I/O wait.  What is the system's swap usage during those time frames?
More than normal?

How about file I/O?  Try supplementing your 'top' monitoring with the
vmstat program.  Try:

fd0man at pepper:~[130]$ vmstat 1 5
procs -----------memory---------- ---swap-- -----io---- --system--
----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy
id wa
 2  0 135684 160760  10232 137620    2    3    13    11  193   131 10  1
88  1
 0  0 135684 160744  10232 137620    0    0     0     0  463   370  2  2
96  0
 0  0 135684 160736  10232 137620    0    0     0     0  493   319  5  3
92  0
 0  0 135684 160720  10232 137620    0    0     0     4  538   416  4  3
93  0
 0  0 135684 160720  10232 137620    0    0     0     0  472   330  4  1
95  0
fd0man at pepper:~[0]$

The first parameter is number of seconds between updates, and the second
parameter is the number of times to report.  It is most useful to run
'vmstat 1' and leave it go if I am trying to figure out where the
bottleneck on things is.  In vmstat, it shows you interrupts, context
switches, and CPU usage by user/system/idle/wait.  The very first line
shows the averages since boot up.

You may want to try using pmap, as well, on the process in question.
That might help to provide a clue, though only a basic clue and not
anything of terrible use, as far as I can tell.  It just shows you what
the memory usage is for various parts of the application.

On init, pmap shows:

fd0man at pepper:~[0]$ pmap 1
1:   init [2]
08048000     28K r-x--  /sbin/init
0804f000      4K rwx--  /sbin/init
08050000    132K rwx--    [ anon ]
b7dee000      4K rwx--    [ anon ]
b7def000   1172K r-x--  /lib/tls/i686/cmov/libc-2.3.6.so
b7f14000     28K rwx--  /lib/tls/i686/cmov/libc-2.3.6.so
b7f1b000     12K rwx--    [ anon ]
b7f29000     12K rwx--    [ anon ]
b7f2c000     84K r-x--  /lib/ld-2.3.6.so
b7f41000      4K rwx--  /lib/ld-2.3.6.so
bfa2b000     88K rw---    [ stack ]
ffffe000      4K -----    [ anon ]
 total     1572K
fd0man at pepper:~[0]$

The "anon" portions, best as I can tell, belong to the program.  I am
currently writing a program and I wanted to see if it had a memory leak
or not -- and I suspected it did -- and the line that reads now 132K for
init grew quite a bit.  I cannot say it is the same for every program,
but my guess is that the line that reads 132K is the "heap" for the
program.  If that number gets very big, the system starts going nuts.  :)

	HTH,
	Mike

-- 
"Fate: Protects fools, children, and ships called /Enterprise/."
                               -- William T. Riker, ST:TNG, "Contagion"


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