James M. Lawrence writes: > On Wed, Sep 2, 2015 at 6:09 AM, Daniel Kochmański <dan...@turtleware.eu> > wrote: >> Hm, then I can't reproduce neither of them. Spawning too many threads >> blows the heap, but it's understandable. I think it might be that i have >> x86_64 and a new kernel, (maybe it happens only on x86, or linux 3.2 had >> some bug?). > > 64-bit systems are sometimes better at concealing such threading bugs. > The default assumption should be that 64-bit systems just haven't been > jiggled to the right tune yet. Over the course of several years, and > across several kernels, I haven't seen any version of ECL pass these > stress tests. This problem would need to be understood before even > thinking about kernel bugs, which seem quite unlikely in this case. >
Ok, so I guess I'll just set up 32-bit VM. I hope this will be able to reproduce the problems (next test doesn't fail neither on my x86_64 for my tests). Yeah, I also think that kernel bug is unlikely, but I'll keep that possibility in mind. I've added your tests to repository and will integrate them soon (infinite loop isn't a good pick for regression tests :-)). Thanks, Daniel > Moving up the ladder of complexity, the next test case requires a > blocking queue and involves repeatedly creating/destroying worker > threads. It has three different types of failures; they are sporadic > and not determined by the inputs. The following are just example runs > and shouldn't be considered representative: > > (qtest 0 64) ;=> segfault > (qtest 1 64) ; => hang > (qtest 10000 64) ; => error "Attempted to recursively lock..." > > ;;;; raw-queue > > (defstruct (raw-queue (:conc-name nil)) > (head nil) > (tail nil)) > > (defun push-raw-queue (value queue) > (let ((new (cons value nil))) > (if (head queue) > (setf (cdr (tail queue)) new) > (setf (head queue) new)) > (setf (tail queue) new))) > > (defun pop-raw-queue (queue) > (let ((node (head queue))) > (if node > (multiple-value-prog1 (values (car node) t) > (when (null (setf (head queue) (cdr node))) > (setf (tail queue) nil)) > (setf (car node) nil > (cdr node) nil)) > (values nil nil)))) > > ;;;; queue > > (defstruct queue > (impl (make-raw-queue)) > (lock (mp:make-lock)) > (cvar (mp:make-condition-variable))) > > (defun push-queue (object queue) > (mp:with-lock ((queue-lock queue)) > (push-raw-queue object (queue-impl queue)) > (mp:condition-variable-signal (queue-cvar queue)))) > > (defun pop-queue (queue) > (mp:with-lock ((queue-lock queue)) > (loop (multiple-value-bind (value presentp) > (pop-raw-queue (queue-impl queue)) > (if presentp > (return value) > (mp:condition-variable-wait > (queue-cvar queue) > (queue-lock queue))))))) > > ;;;; qtest > > (defun qtest (message-count worker-count) > (loop (let ((to-workers (make-queue)) > (from-workers (make-queue))) > (loop repeat worker-count > do (mp:process-run-function > "test" > (lambda () > (loop (let ((message (pop-queue to-workers))) > (push-queue message from-workers) > (unless message (return))))))) > (loop repeat message-count do (push-queue t to-workers)) > (loop repeat message-count do (pop-queue from-workers)) > (loop repeat worker-count do (push-queue nil to-workers)) > (loop repeat worker-count do (pop-queue from-workers)) > (format t ".") > (finish-output)))) -- Daniel Kochmański | Poznań, Poland ;; aka jackdaniel "Be the change that you wish to see in the world." - Mahatma Gandhi
