I don't know if the boss function might be of help to you? It helped
me in order for the current forked instance of the web server to be
able to call the main process and do various slow writes there. The
reason was that the user should not have to wait for stuff like that.,
ie the current child process was able to return an http answer much
faster while the heavy stuff happened in the background.
On Sat, Jun 2, 2012 at 6:48 AM, Jorge Acereda <jacer...@gmail.com> wrote:
> Hi again,
> On May 29, 2012, at 4:40 PM, Alexander Burger wrote:
>>> Another option to avoid the fork() would be to have a pool of
>>> pre-forked instances reading from a jobs queue or something like that
>>> (perhaps taking advantage of an additional database to implement the
>>> queue?), but my skills are still lacking on how to implement that.
>> That's also an interesting approach.
>> An important question is: Does this parallel processing of database
>> objects also involve modifications of these objects? If so, the
>> necessary synchronization between the processes will produce additional
> Yes, I need to update the database with results from the executed commands.
> So, you suggest limiting the updates to happen only in the main process,
> In that case I would need something like the following to be able to invoke
> the shell commands and update the database with the results.
> I don't like it, too convoluted for my taste. Any suggestion on how to
> improve the performance/style? Perhaps a different approach would be better?
> Note that *maxProcesses should be set to something like the number of cores
> and that increasing the length of *L can result in fork() errors in the
> simple later/wait benchmark.
> (setq *maxProcesses 2)
> (setq "*idle" '(NIL NIL nil))
> (setq "*batches" (make (do *maxProcesses (link "*idle"))))
> (de "findPred" (Pred L)
> (seek '((X) (Pred (car X))) L) )
> (de "completeJob" ("Pos")
> (let (cdar "Pos")
> (let RESULT (caar "Pos")
> (eval (caddar "Pos")) ) )
> (set "Pos" "*idle")
> "Pos" )
> (de "waitJob" ()
> ("completeJob" (wait NIL ("findPred" 'pair "*batches"))))
> (de waitAll ()
> (wait NIL (not ("findPred" 'atom "*batches")))
> (map '"completeJob" "*batches"))
> (de batch ("Cont" . "Job")
> (let "Pos" ("waitJob")
> (set "Pos" 'busy)
> (later "Pos"
> (list (run "Job") (env) "Cont") ) ) )
> (mapcar '((X) (batch '(msg RESULT) (* X X))) (range 1 10))
> (de mycmd ()
> (in '(cc "-c" "../picolisp/src/main.c" "-o" "/dev/null")) T)
> (setq *L (range 1 50))
> (mapcar '(() (batch '(nil RESULT) (mycmd))) *L)
> (waitAll) )
> (mapcan '(() (later (cons) (mycmd))) *L)
> (wait NIL (full @))
> ) )
> (mapcan '(() (mycmd)) *L))
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