Hi François,
Many thanks for your reply. As soon as you know more, I would be very
pleased to test again in a new alpha. I would like to have my software
back up-and-running before the actual release of Scilab 6. Before doing
so I will have to decide how to handle the threading issue.
If the solution will be that all is single threaded but in different
threads, I suppose my best work-around would still be to synchronize
access to the underlying objects over a private thread. I hope you will
decide to keep the core thread alive and recycle it between calls, so
that all calls are made on the same thread.
If on the other hand your solution will be full multi-threaded
execution, I would welcome that too. Also in this case I hope you will
create a fixed number of threads and recycle them, for the same reason.
In this case I can simply create a corresponding number of COM objects
under the hood.
I am not sure why events from outside the thread would have to make that
you stop the thread and start another one (unless you forcefully
terminate the thread, but I suppose you do not as this will surely lead
to memory leaks and other trouble). You can simply set up your
calculation thread to do something like
void core_threadproc() {
for (;;) {
//wait until next command
synchronizationObject.wait();
//pick up next (set of) command(s) and execute
if (nextCommand==CommandTerminate()) break;
...
}
}
For interrupting calculations you could poll between individual commands
and during length commands.
On another note: removal of the intersci exe forced me to switch to the
api-scilab (short of keeping previous builds of scilab around). I am
pleased with this interface, it is a lot nicer than intersci. The C++
interface is nicer than the C interface, I think, but does not seem to
have support for strings and some other data types (unless I missed
something). So I am now mixing my approach: "csci" interfaces for all
routines that take string matrices as in- our output, and "cppsci"
interfaces for all routines that only deal with numeric matrices.
Support for string (and other) data types from the cppsci interface
would be welcome in the future.
Best wishes,
Jasper
On 8/5/2015 10:21, François Granade wrote:
Hi Jasper,
Looks like you have found an interesting question here...
First - there are no multiple concurrent threads in the core. So we
are safe (and so is the API, without being thread-safe).
However, what you saw is right: each command executes in a new thread.
We designed it on purpose, with one of the reason being that this
thread can be what we call the "storeCommand" which manages events
from outside the main thread (UI, interruption). Another idea was that
- later - to allow multithreaded execution (under some serious
constraints).
Now, your point about COM loading, and thread-local storage, is very
valid, and may very well mean that we should change this.
We will study if/how we could modify that... we'll keep you posted.
Thanks *a lot* for reporting this; it's exactly what we released the
alpha for, and even though we were hoping we would not have such
questions, it's better to have them now than later...
for the Scilab team,
François Granade
On Aug 4, 2015, at 9:21 AM, jasper van baten <[email protected]
<mailto:[email protected]>> wrote:
Does anybody know what threading model is used in Scilab 6 alpha? I
am referring to the default mode of operation, and not while
executing parallel_for, or MPI as described here
(http://wiki.scilab.org/Documentation/ParallelComputingInScilab).
If there are multiple core threads that execute concurrently, then
all api-scilab code needs to be written in a thread-safe re-entrant
safe manner. I doubt this is the case.
If there is one core thread alive at any point, it would make sense
for this to remain the same thread, which does not appear to be the
case. If not the same thread, any application that depends on
apartment threaded COM objects or thread local storage will no longer
function as it did in Scilab 5. The solution may be to synchronize
such applications over a private thread, but that surely will come at
a performance cost.
Having some idea about the threading model that is intended and used
would be helpful.
Best wishes,
Jasper.
On 7/31/2015 18:35, jasper van baten wrote:
All,
What's the story with threading in Scilab 6? Whereas previous
versions appeared to be single threaded from an external DLL point
of view, I see that the DLLmain function gets called by a one
thread, whereas interface routines get called from another thread.
Worse, looks like each interface routine call is made from a new
thread. What is the threading model?? Is there a limited number of
threads, or are threads created on the fly?
Thanks, best wishes,
Jasper
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