SuperKaramba Memory Sensor Incorrect
I noticed that SuperKaramba reports memory usage differently to the free and
vmsize commands when you select the format="%umb" option (described as "Used
memory in megabytes (cache and buffers excluded)." on the SuperKaramba
sensors page ).
The memory usage appears to be considerably lower than that reported by the
free command. For example, at the moment free outputs the following:
total used free shared buffers cached
Mem: 386948 383360 3588 0 26488 105076
-/+ buffers/cache: 251796 135152
Swap: 562232 355856 206376
whereas my SuperKaramba theme reports the used memory excluding cache and
buffers to be 210Mb (instead of 251796/1024=246Mb).
I had a look at the source code in the Debian package. The memory usage is
found by parsing the /proc/meminfo file. The MemSensor::getCached() function
calculates the amount of cache as the total "Cached" and "SwapCached" memory
and the free memory is calculated using this value. This means that the
reported free memory is lower than that reported by "free" by the amount of
SwapCached memory. I'm pretty sure that this is wrong as SwapCached relates to
the swap partition rather than the physical memory, but I wanted to run it
past you guys before filing a bug. Also, is this better filed with the Debian
BTS or upstream?
Using pure Sid, stock kernel 2.6.8, SuperKaramba version 0.35-2.