Need accurate memory usage statistics to figure out what size matrix I can work with without choking the RAM on this laptop. ;)
I am using top to figure out how much memory an app I'm working on is using.
The issue is that I do not understand the information that is presented?
Specifically, it says I'm using ~6.5gigs out of 7.8 gigs, which would be about 85% of all memory. The column that's called %MEM says the process is using 15.0 and chrome is using another ~5.4. I don't understand what used is and what %MEM is.
top - 11:15:04 up 1:15, 4 users, load average: 2.12, 1.52, 1.18
Tasks: 230 total, 2 running, 228 sleeping, 0 stopped, 0 zombie
%Cpu(s): 27.6 us, 0.2 sy, 0.0 ni, 72.1 id, 0.1 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 7861188 total, 6516808 used, 1344380 free, 95792 buffers
KiB Swap: 0 total, 0 used, 0 free. 3697392 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2753 arthur 20 0 1320032 1.121g 6732 R 100.0 15.0 58:35.05 svd_all_ri_clus
3481 arthur 20 0 1261924 222324 22736 S 4.0 2.8 0:08.09 chrome
3512 arthur 20 0 1232108 204356 22396 S 2.3 2.6 0:06.60 chrome
2461 arthur 20 0 666052 25800 13436 S 1.7 0.3 0:06.95 gnome-terminal
1343 root 20 0 393284 83852 74748 S 1.3 1.1 0:11.93 Xorg
2208 arthur 20 0 1332004 101584 32700 S 0.7 1.3 0:18.16 compiz
3345 arthur 20 0 1506568 124560 59936 S 0.7 1.6 0:10.73 chrome
3411 arthur 20 0 785080 108416 19364 S 0.7 1.4 0:06.34 chrome
10 root 20 0 0 0 0 S 0.3 0.0 0:00.19 rcuos/2
1177 root 20 0 30608 2752 2144 S 0.3 0.0 0:00.12 wpa_supplicant
1937 arthur 20 0 361956 4328 2884 S 0.3 0.1 0:02.93 ibus-daemon
2007 arthur 20 0 480028 15864 10876 S 0.3 0.2 0:00.88 ibus-ui-gtk3
3047 root 20 0 0 0 0 S 0.3 0.0 0:00.26 kworker/u16:0
Just in case someone says read the man page, I already did (skimmed through it).
Does not appear to explain the difference between "used" and the sum total of what is listed under %MEM.
2c. MEMORY Usage
This portion consists of two lines which may express values in kibibytes (KiB) through
exbibytes (EiB) depending on the scaling factor enforced with the 'E' interactive command.
Line 1 reflects physical memory, classified as:
total, used, free and buffers
Line 2 reflects mostly virtual memory, classified as:
total, used, free and cached (which is physical memory)
This table may help in interpreting the scaled values displayed:
KiB = kibibyte = 1024 bytes
MiB = mebibyte = 1024 KiB = 1,048,576 bytes
GiB = gibibyte = 1024 MiB = 1,073,741,824 bytes
TiB = tebibyte = 1024 GiB = 1,099,511,627,776 bytes
PiB = pebibyte = 1024 TiB = 1,125,899,906,842,624 bytes
EiB = exbibyte = 1024 PiB = 1,152,921,504,606,846,976 bytes
3. FIELDS / Columns
3a. DESCRIPTIONS of Fields
Listed below are top's available process fields (columns). They are shown in strict ascii
alphabetical order. You may customize their position and whether or not they are displayable
with the 'f' or 'F' (Fields Management) interactive commands.
Any field is selectable as the sort field, and you control whether they are sorted high-to-
low or low-to-high. For additional information on sort provisions see topic 4c. TASK AREA
Commands, SORTING.
The fields related to physical memory or virtual memory reference '(KiB)' as the default,
unsuffixed display mode. Such fields can, however, be scaled differently via the 'e' inter‐
active command.
1. %CPU -- CPU Usage
The task's share of the elapsed CPU time since the last screen update, expressed as a
percentage of total CPU time.
In a true SMP environment, if a process is multi-threaded and top is not operating in
Threads mode, amounts greater than 100% may be reported. You toggle Threads mode with
the 'H' interactive command.
Also for multi-processor environments, if 'Irix mode' is Off, top will operate in
'Solaris mode' where a task's cpu usage will be divided by the total number of CPUs. You
toggle 'Irix/Solaris' modes with the 'I' interactive command.
2. %MEM -- Memory Usage (RES)
A task's currently used share of available physical memory.
It shows the number of amount RAM used