[systemd-devel] [PATCH] bootchart: use conf-parser & CamelCase names in .conf

[Kok, Auke-jan H]

On Wed, Feb 13, 2013 at 3:32 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Wed, 13.02.13 14:27, Kok, Auke-jan H (auke-jan.h.kok at intel.com) wrote:
>
>> > Hmm, what does this stand for? Wikipedia doesn't have it, can't be that
>> > well known...
>>
>> PSS is the alternative to RSS... You probably won't find an
>> explanation anywhere else but the kernel source code:
>>
>> Documentation/filesystems/proc.txt:
>> =====
>> The /proc/PID/smaps is an extension based on maps, showing the memory
>> consumption for each of the process's mappings. For each of mappings there
>> is a series of lines such as the following:
>>
>> 08048000-080bc000 r-xp 00000000 03:02 13130      /bin/bash
>> Size:               1084 kB
>> Rss:                 892 kB
>> Pss:                 374 kB
>>
>> [...]
>>
>> The first of these lines shows the same information as is displayed for the
>> mapping in /proc/PID/maps.  The remaining lines show the size of the mapping
>> (size), the amount of the mapping that is currently resident in RAM (RSS), the
>> process' proportional share of this mapping (PSS),
>> =====
>>
>> so, PSS translates to "proportional share of the mapping(size) that is
>> resident in RAM"
>>
>> PSS will do fine, I suppose :^)
>
> RSS is an acronym for "Residential Set Size". PSS for
> "Propertional Set Size". Hence the option for bootchart should be
> "ProportionalSetSize="?
>
> What does the option actually do? Do we actually need the option? If
> not, we might just drop this source of confusion? And we do need it,
> maybe make it explanatory as int "PlotProportionalSetSize=" or so?

When enabled, it creates an additional graph (just like the entropy
option, or, if you have booted with initcall_debug) that plots the PSS
for each process.

It's a highly usable graph for people working on systems with less
memory, so, I'd like to keep it.

Example of how it looks here:

    http://foo-projects.org/~sofar/bootchart-20120401-0710.svg

Plotting of PSS is disabled by default since it has quite a
performance impact (it requires parsing /proc/<NN>/smaps for each
process, which can be hundreds of kilobytes large each).

Auke