[Toybox] ps and top (and Android)

[enh]

as for top, i think once my pcy patch (or something like it) is in,
that's almost there too...

* the TOP_COMMON help isn't getting included in "top --help".

* no -H to work on threads rather than processes.

* (probably related to this, -O tcnt shows all 0s.)

* no -O pcy, but thanks to sharing we'll get that for free from ps.

* the Android top had a -m N option to only show the top N. i think
this was a bad idea (because interactively we should query the
terminal, and the only batch mode usage i know of is when collecting a
bugreport and in N that's a zip rather than one long text file, so i
don't think there's any reason not to just include everything now ---
"top n" seems pretty bogus anyway; you're probably more interested in
"anything greater than V in column C"). so unless you think this is a
good idea, i'd rather see if anyone notices and has a good reason to
add this. (there's some argument that "i can't just use head because
of the header", but that's a fixed number of lines and/or you can
supply -q if you don't want the header at all.)

* speaking of headers, trying to find problems before they find me i
did find a couple of uses in the tree of GNU ps' --no-headers option.
obviously they're in scripts meant for the host, but i thought you
might be interested anyway.

On Sat, Apr 30, 2016 at 9:50 AM, enh <enh at google.com> wrote:
> On Fri, Apr 29, 2016 at 6:06 PM, enh <enh at google.com> wrote:
>> On Fri, Apr 29, 2016 at 5:45 PM, Rob Landley <rob at landley.net> wrote:
>>> On 04/29/2016 04:06 PM, enh wrote:
>>>> sorry, hadn't had time to look until now. notes:
>>>>
>>>> * the tid column seems very wrong. in particular, i see a lot of
>>>> duplicate tids. ah, the pid/tid columns don't auto-expand and are
>>>> truncating...
>>>>
>>>> GNU: 147139 130820 ?        00:00:00 default_ThreadM
>>>> toybox: 14713 13082 ?        00:00:00 default_ThreadM
>>>
>>> Hmmm, this sounds like a problem for PIDs too.
>>
>> (yeah, sorry --- you can see that in my example above but i forgot to
>> actually call it out.)
>>
>>> Let's see...
>>>
>>> $ ps -o pid:3,user:3,cmd:3
>>> PID USER CMD
>>> 18748 la+ bash
>>> 19147 la+ ps -o pid:3,user:3,cmd:3
>>>
>>> Ok,  I need to mark some columns as "expand this regardless" and others
>>> to indicate when they get truncated, and yet it truncates the cmdline at
>>> the right edge of the screen without indicating truncation...
>>>
>>> Hmmm... It's not quite obvious to me what the correct behavior is.
>>> (Numeric fields expand, command lines are silently truncated,
>>> non-command string fields do the + thing...? Maybe?)
>>>
>>>> * your -T is (like the desktop) showing the process name for each
>>>> thread. Android shows the thread name, which is probably what you want
>>>> if you're asking to see the threads in the first place.
>>>
>>> There's a thread name? Ah, the stat[2] field gets rewritten.
>>
>> in the pthread implementation we read/write /proc/self/task/%d/comm.
>> toolbox's ps shows the text between ()s in the stat file. since you
>> have to read that anyway, that probably makes sense.
>>
>>> How about if I treat PID != TID the same as kernel threads? [stat2name]
>>> in square brackets?
>>
>> i reserve the right to come back later with strong negative feedback
>> from users, but that sounds good to me. it might actually be useful to
>> have a visible "not the main thread" distinction that doesn't require
>> skipping back to the pid/tid columns.
>
> i see you committed an implementation already. looks good to me so
> far. as i predicted, i quite like the at-a-glance "this is a thread"
> signal.
>
>>>> * you say 0 for BIT when you don't know, rather than leaving it blank
>>>> (like Android) or using '-' (like some other ps fields). i don't think
>>>> this matters, but i've attached a patch anyway.
>>>
>>> Applied.
>>>
>>>> * there's a whitespace mixup in the help text for -O. patch attached.
>>>
>>> Applied.
>>>
>>>> * i need to send you the Android-specific cruft for scheduling policy.
>>>
>>> Woot.
>>
>> you say that because you haven't seen it yet :-)
>>
>> attached. i kept the #ifs in lib/portability.* because there was no
>> obvious way to just say "this field isn't useful outside of Android".
>>
>>>> other than that, i went through my old notes and i think everything
>>>> else is now done. i'll get AOSP synced this afternoon (must be friday
>>>> again!) and send you a patch for the scheduling policy names.
>>>
>>> I'll try to figure out what to do about column expansion. (Mental note:
>>> how does this impact top not wrapping lines and thus scrolling the
>>> screen...)
>>>
>>> Rob
>>
>>
>>
>> --
>> Elliott Hughes - http://who/enh - http://jessies.org/~enh/
>> Android native code/tools questions? Mail me/drop by/add me as a reviewer.
>
>
>
> --
> Elliott Hughes - http://who/enh - http://jessies.org/~enh/
> Android native code/tools questions? Mail me/drop by/add me as a reviewer.



-- 
Elliott Hughes - http://who/enh - http://jessies.org/~enh/
Android native code/tools questions? Mail me/drop by/add me as a reviewer.