Running a skill procedure in the background and some interval.

Whats the best and easiest way to run a skill process, a procedure in
the background.
For example for the following two procedures,,
procedure(trial()
hiRegTimer("t1() trial()" 10)
)

procedure( t1()
printf("Hmm..\n")
)

I would like to run t1 in the background every second, if and only if
the previous t1() function has completed

Thanks,
Partha

 

Well, bear in mind that SKILL isn't multithreaded. What that means is that any
SKILL function being scheduled by hiRegTimer() will only run when it returns to
the top level event loop - this means that if a SKILL function is already
running, the next scheduled timer function will not start until it completes.

However, you may be asking how to get it so that it doesn't schedule another run
if a previous call has complete successfully (whatever "successfully" means in
your case). This would normally be done by using a semaphore (e.g. a global
variable) which is used to indicate the success/failure of an operation. Then
you'd check that semaphore to decide whether you want to schedule it to run
again.

You do need to be careful scheduling something to run with 1 second intervals
that you don't mess up the performance of the tools; if the code takes any
significant time to run, it's going to impact interactive performance.

Regards,

Andrew.

 

Andrew,
Thanks for your input, that is what I feared.
Can you please furnish an example of the semaphore, not clear to me
from the post above.
So when V-XL talks about running the connectivity extractor in the
background, it is not a truly backgrounded process?

I came with the following way to try and run a skill process
periodically from shell, Is this a good solution? ( I still have many
things to figure out, since I know dbAccess only supports a subset of
functions).
Or is ipcSkillProcess a better alternative?

I was informed by someone that there is this thing called MPS..( multi
process skill?). Is it true?

Thankyou .
Partha


procedure(trial1(ipcId exitStatus)
printf("f\n")
hiRegTimer("t1() " 10)
)

procedure( t1()
let((cv)
printf("%s\n" getCurrentTime())
cv = deGetCellView()
(ipcBeginProcess sprintf( nil "/home/pvn/runS.sh %s" cv) "" nil nil
'trial1)
))

And then in file runS.sh

#!/bin/sh
args="$*"
argn=$#
dest=`echo ${args} | cut -f${argn} -d' '`
echo $dest
dbAccess << EOF|tail -1
myP = outfile("/home/pvn/hah")
fprintf( myP "printing...$d\n" 1)
foreach( inst $dest~>instances
fprintf( myP "printing...%s\n" inst~>cellName)
)
close(myP)

 

Hi Partha,

No. It is something that is triggered when you make changes in the layout - and
it is done at the C level. It's not a background process. It does some
incremental extraction as you make changes in the layout.

This approach is fine - although you obviously have to be careful about
making any changes to the database because it would be locked separately
as it's a separate process.

I don't think ipcSkillProcess would help necessarily - that just provides you
an additional pair of ports to send SKILL commands and results via. It can be
useful at times.

In short, there are a variety of different approachs you might take - and it
depends on exactly what you're doing as to which makes most sense!

MPS is a remote procedure call mechanism. It was formerly called "Multi Process
SKILL" but was renamed "Message Passing Subsystem" because it is used in
non-SKILL tools too.

However, this is not something that is a public, documented, capability and so
you should not use it - it is liable to change, and is not supported for
customer use.

Regards,

Andrew.

 

Fantastic!
Thanks Andrew.
Partha