Re: crashes with Fibers

[Amirouche Boubekki <amirouche@hypermove.net>]

On 2018-07-02 00:41, Amirouche Boubekki wrote:
> On 2018-07-02 00:32, Amirouche Boubekki wrote:
>> On 2018-07-01 15:09, Clément Lassieur wrote:
>>> Amirouche Boubekki <amirouche@hypermove.net> writes:
>>> 
>>>> Sorry, I did not read the code. What are you trying to achieve?
>>> 
>>> Within a fiber, I need to spawn several Guile-Git clones in parallel.
>>> Since they block the Fibers scheduler, they need to be in separate
>>> threads.
>> 
>> I tried that in the past it was working, but don't remember correctly
>> how I did.
> 
>> epoll is dead seems to indicate that there is no fiber scheduler 
>> running
>> from the thread your are calling put-message. This might be a design 
>> decision
>> or not. My understanding is that your code should work as intended.
> 
> You test5 code should definitly work. Otherwise, it requires to 
> pre-allocate
> as many thread as you need before you know you will them. May be we can 
> look
> at it backward and say, that allocating a pool of threads in advance is 
> more
> interesting performance wise.
> 
>> Anyway, try to spawn the thread and/or create the channel before you
>> run fibers. I can't try that myself because of my slow connection 
>> which
>> takes ages to install guile-fibers.
>> 
>> Something like:
> 
> (use-modules (fibers))
> (use-modules (fibers channels))
> 
>> (define (test6)
>>   (let ((channel (make-channel)))
>>     (call-with-new-thread
>>      (lambda ()
>>        (put-message channel "hello world")))
>>     (run-fibers
>>      (lambda ()
>>        (spawn-fiber
>>         (lambda ()
>>           (format #t "~a~%" (get-message channel)))))
>>     #:drain? #t)))
> 
> It works on my side.

FWIW, the following code doesn't crash, but apparently does nothing:

(define (test7)
   (let ((channel (make-channel)))
     (run-fibers
      (lambda ()
        (spawn-fiber
         (lambda ()
           (call-with-new-thread
            (lambda ()
              (put-message channel "hello world")))
           (format #t "~a~%" (get-message channel)))))
     #:drain? #t)))