Operating Systems > Linux and UNIX
Vector Linux
Aloone_Jonez:
Memory usage under fluxbox while running X-term and X-calc, in the root user area.
Total: 218.46, I have 224MB of system memory, so what's happened to the last 5.54MB?
Used: 97.93MB
Free: 120.54MB
Buffers: 7.91MB
Cached: 60.33MB
The swap partition was completely unused!
X is the biggest resource hog using 8%, the other processes all used less than 2%, 1% was the norm. I added all this up and it came to 15%, these figures are probably rounded up anyway so it's probably far less than 15%.
97.93 - 7.91 - 60.33 = 29.69 = 13.59% of total memory!
This is all very good but why dose Linux allocate large amounts of memory for a Cache?
I wouldn't like to run this on 32MB of memory.
[ August 09, 2004: Message edited by: Aloone ]
insomnia:
quote:Originally posted by Aloone:
I wouldn't like to run this on 32MB of memory.
[ August 09, 2004: Message edited by: Aloone ]
--- End quote ---
I would(and I did). ;)
Aloone_Jonez:
quote:Originally posted by insomnia:
I would(and I did). ;)
--- End quote ---
It must allocate memory according to your hardware, I would imadgine if you only had 32MB it would load less and use the swap partition more.
This is very good as, RedHat often used the swap partition causing my PC to slow to a crawl on some occasions, this hasn
KernelPanic:
Linux puts alot of data to cache to improve performance. Whereas Windows often leaves large amounts of memory unused, what Linux does in this situation is different.
Instead of memory that isn't allocated to an application or the kernel being 'free' (read: wasted) Linux uses this for caching data.
Now I don't know all the exact details of how this works, but I believe it improves performance considerably. I think all UNIX systems I/O buffer in this way. You could read the kernel source if you are really interested.
I think that when you open an application that asks for a chunk of memory and there is none free the kernel just flushes some of the cache. This way news apps can still run.
Seriously though, look through mm/ in the kernel source i'm sure it can explain it better than me
WMD:
Cache size is determined by system memory. If you have 32MB in the system, it'll probably used about 8MB for it (at least that's what my 32MB system did). As for the lost 5MB of memory it isn't reporting, I have no clue. It always seems to report a smaller number on all machines.
On this note...is there something that lets me control the size of the caches? Because my system, after a half hour or so, seems to go up to 100MB buffers and 260MB cache, which puts it really close to the top.
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