[Libre-soc-bugs] [Bug 199] Layout using coriolis2 main core, 180nm

[bugzilla-daemon at libre-soc.org]

https://bugs.libre-soc.org/show_bug.cgi?id=199

--- Comment #34 from Luke Kenneth Casson Leighton <lkcl at lkcl.net> ---
(In reply to Jean-Paul.Chaput from comment #33)
> > > --2020-07-22 16:50:30--  https://ftp.libre-soc.org/nohup.out.bz2
> > 
> > # chmod ugo+r ./nohup.out.bz2
> > 
> > try again
> 
> OK. When looking at the log file, I did see that you did make the P&R
> twice... 

i did?  i didn't!  however i did run "make cgt" in a separate window
in order to get the... no wait, that was before doing this run.

wasn't me, boss

> As it is deterministic, you get twice the same result, *but*
> very strangely, the second run is much slower than the first.
> 
> Runs:
>    Place       GlobR   BDetR   LAssign   DetR   Destroy   Total
> 1    394 + 2 +    58 +    34 +     685 +  270 +       3   1446 (24 minutes)
> 2   1496 + 8 +   226 +   137 +    2205 + 1010 +       8   5090 (84 minutes)
> 
> You can find those times by searching for 'Done in' in the log file.
> 
> There may be a flaw in the Makefile system. As the routage fails a
> "failed" status is returned to the calling rule, so it may start again
> the P&R. Did you just made a "make lvx" or "make layout; make lvx" ?

"make layout" and in a separate window i had run "make cgt" - *before*
starting this run.

> I'm also curious about why so different runtimes. Was your computer
> much more loaded the second time? 

not really.  it is 8-core dual hyper-threaded

> Or did you not throttle the CPU the
> first time?

once it's set up it's a pain to change, so no change.

> You can see that LAssign (Layer Assignment) takes more times than
> the whole placement. This is not normal considering what it does.
> So, if I find what's wrong we can win almost 10 minutes over 24...

and if i let it run at 5ghz that saves time, too.

btw one other reason i really want to do sub-cell layouts is to have
the possibility of parallel make.

l.

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