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

[Kay Sievers]

On Thu, Feb 14, 2013 at 12:42 AM, Kok, Auke-jan H
<auke-jan.h.kok at intel.com> wrote:
> 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).

That looks nice, yeah.

But shouldn't it just be called PlotMemoryUsage= or something instead
of the using the "algorithm name" in the config switch to enable it?

Kay