free and top command.

manoj.linux · 12-06-2013, 02:49 AM

Hi,

I have used top and free command.

I would like to know why there is difference in buffers for using top and free command?

druuna · 12-06-2013, 04:04 AM

There shouldn't be a difference.

How did you test this?
- If you run top and free side-by-side the amount shown should be the same.
- If you run one after the other there is a chance that the amount shown differs.

syg00 · 12-06-2013, 04:06 AM

Buffers are always being allocated/freed, so changes continually. Top and free both use /proc/meminfo as source of their output, so should be mighty close.
Make sure you use kilobytes as the comparison.

manoj.linux · 12-06-2013, 04:29 AM

Quote:

Originally Posted by syg00

Buffers are always being allocated/freed, so changes continually. Top and free both use /proc/meminfo as source of their output, so should be mighty close.
Make sure you use kilobytes as the comparison.

Basically I would like to know.

from below output.How to read or relate one marked in bold

[test]$ free -m
total used free shared buffers cached
Mem: 129176 92753 36423 0 2268 39973
-/+ buffers/cache: 50511 78664
Swap: 31996 0 31996

[test ~]$ top
top - 12:31:48 up 7 days, 1:26, 3 users, load average: 0.75, 1.12, 1.20
Tasks: 995 total, 1 running, 994 sleeping, 0 stopped, 0 zombie
Cpu(s): 3.3%us, 1.2%sy, 0.0%ni, 95.4%id, 0.0%wa, 0.0%hi, 0.1%si, 0.0%st
Mem: 132276504k total, 94983252k used, 37293252k free, 2322436k buffers
Swap: 32764556k total, 0k used, 32764556k free, 40933180k cached

syg00 · 12-06-2013, 04:49 AM

Code:

             total       used       free     shared    buffers     cached
Mem:        129176      92753      36423          0       2268      39973
-/+ buffers/cache:      50511      78664
Swap:        31996          0      31996

[test ~]$ top
top - 12:31:48 up 7 days,  1:26,  3 users,  load average: 0.75, 1.12, 1.20
Tasks: 995 total,   1 running, 994 sleeping,   0 stopped,   0 zombie
Cpu(s):  3.3%us,  1.2%sy,  0.0%ni, 95.4%id,  0.0%wa,  0.0%hi,  0.1%si,  0.0%st
Mem:  132276504k total, 94983252k used, 37293252k free,  2322436k buffers
Swap: 32764556k total,        0k used, 32764556k free, 40933180k cached

Like I said, if you used kilobytes in the free command it would be more obvious - and use [code] tags to maintain the display.

The +/- line refers to adjusting the memory usage by the buffer/cache amounts. Helps to equate the numbers in the GUI monitors.

druuna · 12-06-2013, 04:55 AM

Those 2 aren't related.

free:

Code:

             total       used       free     shared    buffers     cached
Mem:      12326940    2479260    9847680          0     139588    1551800
-/+ buffers/cache:     787872   11539068
Swap:      5857272          0    5857272

top:

Code:

Tasks: 353 total,   2 running, 350 sleeping,   0 stopped,   1 zombie
Cpu(s):  0.3%us,  0.2%sy,  0.0%ni, 99.5%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  12326940k total,  2478756k used,  9848184k free,   139588k buffers
Swap:  5857272k total,        0k used,  5857272k free,  1551800k cached

EDIT: Too slow......