89 lines
3.3 KiB
Scheme
89 lines
3.3 KiB
Scheme
;;; watchdog.scm -- Monitor fibers scheduling.
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;;; This file is part of Cuirass.
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;;;
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;;; Cuirass is free software: you can redistribute it and/or modify
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;;; it under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation, either version 3 of the License, or
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;;; (at your option) any later version.
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;;;
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;;; Cuirass is distributed in the hope that it will be useful,
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;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with Cuirass. If not, see <http://www.gnu.org/licenses/>.
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(define-module (cuirass watchdog)
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#:use-module (cuirass logging)
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#:use-module (cuirass utils)
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#:use-module (fibers)
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#:use-module (fibers channels)
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#:use-module (fibers internal)
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#:use-module (fibers operations)
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#:use-module (ice-9 match)
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#:use-module (ice-9 threads)
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#:export (start-watchdog))
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(define* (watchdog-fiber scheduler channel
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#:key
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(period 1))
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"Spawn a fiber running on SCHEDULER that sends over CHANNEL, every PERIOD
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seconds, the scheduler name and the current time."
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(spawn-fiber
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(lambda ()
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(while #t
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(put-message channel (list (scheduler-name scheduler)
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(current-time)))
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(sleep period)))
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scheduler))
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(define* (start-watchdog #:key (timeout 5))
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"Start a watchdog checking that each Fibers scheduler is not blocked for
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more than TIMEOUT seconds.
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The watchdog mechanism consists in spawning a dedicated fiber per running
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Fiber scheduler, using the above watchdog-fiber method. Those fibers send a
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ping signal periodically to a separate thread. If no signal is received from
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one of the schedulers for more than TIMEOUT seconds, a warning message is
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printed."
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(define (check-timeouts pings last-check)
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(let* ((check-period timeout)
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(cur-time (current-time))
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(diff-check (- cur-time last-check)))
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(if (> diff-check check-period)
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(begin
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(for-each
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(match-lambda
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((scheduler . time)
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(let ((diff-ping (- cur-time time)))
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(when (> diff-ping timeout)
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(log-message "Scheduler ~a blocked since ~a seconds."
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scheduler diff-ping)))))
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pings)
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cur-time)
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last-check)))
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(let ((watchdog-channel (make-channel)))
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(parameterize (((@@ (fibers internal) current-fiber) #f))
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(call-with-new-thread
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(lambda ()
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(let loop ((pings '())
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(last-check 0))
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(let ((operation-timeout 10))
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(match (perform-operation
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(with-timeout
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(get-operation watchdog-channel)
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#:seconds operation-timeout
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#:wrap (const 'timeout)))
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((scheduler ping)
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(loop (assq-set! pings scheduler ping)
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(check-timeouts pings last-check)))
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('timeout
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(loop pings
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(check-timeouts pings last-check)))))))))
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(fold-all-schedulers
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(lambda (name scheduler seed)
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(watchdog-fiber scheduler watchdog-channel))
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'())))
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