From: Michael Tremer <michael.tremer@ipfire.org>
Date: Thu, 27 Apr 2023 15:32:54 +0000 (+0000)
Subject: jobs: Refactor the dispatch algorithm to dispatch mutliple jobs at once
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cadd9144499fd18f7f5812f3f7842483bf464700;p=pbs.git

jobs: Refactor the dispatch algorithm to dispatch mutliple jobs at once

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/buildservice/jobs.py b/src/buildservice/jobs.py
index 2c95eff6..fbc27375 100644
--- a/src/buildservice/jobs.py
+++ b/src/buildservice/jobs.py
@@ -6,6 +6,7 @@ import gzip
 import hashlib
 import logging
 import os
+import queue
 import shutil
 
 import pakfire
@@ -152,29 +153,46 @@ class Queue(base.Object):
 		"""
 		log.debug("Dispatching jobs...")
 
-		# Process all builders and assign jobs
-		# We prioritize builders with fewer jobs
+		# Create a queue for all builders
+		builders = queue.SimpleQueue()
+
+		# Add all builders to the queue in ascending order of running jobs
 		for builder in sorted(self.backend.builders.connections, key=lambda b: len(b.jobs)):
+			# Skip builders that are not ready
+			if not builder.is_ready():
+				continue
+
+			builders.put(builder)
+
+		# Run for as long as we have unprocessed builders
+		while not builders.empty():
+			# Take the first builder
+			builder = builders.get()
+
 			log.debug("  Processing builder %s" % builder)
 
 			with self.backend.db.transaction():
-				if not builder.is_ready():
-					log.debug("  Builder %s is not ready" % builder)
-					continue
-
 				# We are ready for a new job
 				job = self.pop(builder)
-				if job:
-					try:
-						builder.dispatch_job(job)
 
-					# Ignore if the builder suddenly went away
-					except BuilderNotOnlineError:
-						pass
+				# If no job could be found for this builder, we simply continue
+				if not job:
+					log.debug("  No jobs processable for %s" % builder)
+					continue
+
+				# If we have a job, we dispatch it to the builder
+				try:
+					builder.dispatch_job(job)
 
+				# Ignore if the builder suddenly went away
+				except BuilderNotOnlineError:
 					continue
 
-				log.debug("  No jobs processable for %s" % builder)
+			# If the builder has not any free slots remaining, we put it back in the
+			# queue to fill it up, but we give priority to builders who have fewer
+			# jobs to run.
+			if len(builder.jobs) < builder.max_jobs:
+				builders.put(builder)
 
 		# Auto-scale builders
 		await self.backend.builders.autoscale()