pt-summary reports wrong memory size

[Tibor Korocz]

Hi,

On a server with 256G memory pt-summary reports 2.5G of memory. See results below:

# free -m
             total used free shared buffers cached
Mem: 258207 256696 1510 383 463 32271
-/+ buffers/cache: 223961 34245
Swap: 16383 39 16344

# free -mh
             total used free shared buffers cached
Mem: 252G 251G 1.0G 505M 463M 31G
-/+ buffers/cache: 218G 33G
Swap: 15G 39M 15G

# cat /proc/meminfo
MemTotal: 264404376 kB
MemFree: 1231712 kB
Buffers: 474832 kB
Cached: 33537260 kB
SwapCached: 2824 kB
Active: 225141140 kB
Inactive: 34971456 kB

Pt-summary:

# Memory #####################################################
       Total | 2.5G
        Free | 1.7G
        Used | physical = 2.5G, swap allocated = 1.6G, swap used = 39.9M, virtual = 2.5G
      Shared | 244.0k
     Buffers | 436.0M
      Caches | 3.1G

Checking the code :
https://github.com/percona/percona-toolkit/blob/2.2/bin/pt-summary#L1171

We can see pt-summary use `free -b`:

free -b
             total used free shared buffers cached
Mem: 2707500810 2700511313 698949632 233472 486223872 3480769740
-/+ buffers/cache: 2347572101 3599287091
Swap: 1717986508 41594880 1713827020

And here we are:

2707500810 bytes is 2.5G.

Not sure this is a bug in the tool or not, but we might can check `meminfo`
 results also and if they are not the same, show a warning or something.

Thanks,
Tibi

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-716