Am 25.02.2013 um 19:02 schrieb Tom Easterday:

> On Feb 25, 2013, at 12:21 PM, Michael Haberler <mai...@mah.priv.at> wrote:
>> try strace ...
> 
> 
> Output from "strace -o filename halcmd -s show pin wcomp.3.max" is here:
> http://bgp.nu/~tom/pub/1204.trace.txt  12.04/Xenomai on Atom 2700  
> http://bgp.nu/~tom/pub/1004.trace.txt  10.04/rtai on Atom 2500
> 
> Not sure what I should be looking for in here but I see some "No such file or 
> directory" errors in the 12.04 version:

'man strace' will tell you that system call timing can by had by the -c and -r 
switches, for instance:

 strace -r  halcmd show pin

looking at the system call timestamps should give a clue where time is spent 
since it's for sure not the application code per se, which is trivial in this 
case

You will _always_ see  "No such file or directory"  'errors' and that is not an 
error you need to be concerned about - that is just the dynamic loader trying 
to open shared libraries along the loader path, which you can tell from the 
pathnames

What is obvious is that your 12.04 version tries many more shared library 
directories that the 10.04 version. However, part of that is a consequence of 
the run-in-place build, or a different dynamic loader behaviour, and has 
nothing to do with the application code:

typical example: open("/home/tom/linuxcnc-rtos/lib/libreadline.so.6", 
O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory) 
-----------------------^^^^^^^^^^^^^^^^^^^^^^^^^^^

This is a system-wide shared library, but due to the run-in-place build it 
tries the local lib directory first, before succeeding on the one installed in 
/lib:

open("/lib/i386-linux-gnu/libreadline.so.6", O_RDONLY|O_CLOEXEC) = 3

Summary: to make figures comparable, you need comparable build options.

---

That said: what exactly is the tuning effort about? There are various ways to 
access pins, and I think pretty much all of them would be orders of magnitude 
faster than 'halcmd show pin x' ?

- Michael




> -Tom
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