Bruno Lustosa wrote:
Yes, but what caught my eyes was not the virtual address space. The
resident portion (i.e., what is really allocated on real memory) is
huge for that first instance. 204mb is way too much for a firefox with
4 tabs open.
I'm not so sure that the resident memory number can be trusted. For
example, consider:
PID %MEM VIRT RES CODE DATA SWAP SHR COMMAND
7749 25.6 642m 518m 3020 61m 123m 514m vmware-vmx
12487 3.7 176m 75m 228 73m 101m 48m soffice.bin
793 2.1 100m 42m 64 72m 58m 17m thunderbird-bin
12056 1.8 63228 37m 1292 25m 24m 11m X
7730 1.3 34412 25m 6180 11m 8376 13m vmware
25627 1.2 77328 24m 60 48m 51m 15m firefox-bin
12444 0.9 30352 17m 36 2156 12m 14m konqueror
12460 0.9 30440 17m 36 2244 12m 14m konqueror
12429 0.8 26896 16m 36 2732 9844 13m kicker
12427 0.8 24580 15m 36 2304 8332 12m kdesktop
10067 0.8 28116 15m 4 2364 11m 12m kate
12407 0.7 26192 14m 36 2032 10m 12m kded
12436 0.7 23976 14m 528 2872 8736 11m superkaramba
8482 0.7 25004 14m 36 2172 10m 11m konsole
9112 0.7 24932 14m 36 2100 10m 11m konsole
12438 0.7 24900 14m 60 1812 10m 11m korgac
12461 0.7 27752 13m 36 1316 13m 11m knotify
12425 0.7 22820 13m 36 1872 9036 10m kwin
12433 0.6 21548 11m 36 1172 9472 9m klipper
12424 0.5 21388 10m 36 1172 9m 9336 ksmserver
12421 0.5 21064 10m 36 1028 9.9m 9216 kaccess
If you sum the RES column of just these programs, you get 928M. Even if
you exclude vmware (which is a bit of a special case), you get 410M.
But now look at what free reports:
total used free shared buffers cached
Mem: 2075856 1923320 152536 0 76552 1552256
-/+ buffers/cache: 294512 1781344
Swap: 3145720 184 3145536
Free claims only 294MB is actually in use on the entire system, and is
accurate. Everything else is backed by disk, so could be discarded and
re-read from disk if necessary.
As far as I know, the only reliable way to determine the actual amount
of memory used by a program is to close it, and look at the difference
reported by free. When I do that test with firefox, the system reclaims
approximately 9.5MB of memory. With openoffice, I get back about 24MB.
It might be that RES - SHR could give you the actual amount, but I'm not
sure of that.
From top output, isn't the SHR the shared memory between them? It's at
16mb for the first, and 17mb for the second. This is still too little
compared to 204mb or 511mb.
SHR is both shared memory (rare), and memory-mapped files (shared
libraries fall here). Notice my vmware output claims 514MB of shared
memory. This is because the guest OS is allocated 512MB of memory,
which exists as a memory-mapped file. Only part of that file may be
physically located in memory at any one time.
-Richard
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