bitbake: cooker: Split recipes to parse amongst threads ahead of time

We have two choices, split the recipes amongst the parsing threads in
blocks ahead of time, or have a queue which parsers pull from when idle.

The optimum approach depends on how similar the pieces are. For the single
recipe reparse case, there is currently a significant wait for the feeder
thread to start (around 0.25s in a 2s command).

Its possible splitting into blocks in advance may be unluckly for some other
workloads but experimentally it seems to work better overall for me at least.

(Bitbake rev: ae79868861568d673a70472e85a4bde9e2d84a8f)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 6 insertions, 11 deletions

diff --git a/bitbake/lib/bb/cooker.py b/bitbake/lib/bb/cooker.py
index d1d2868d6f..e6b8d880ae 100644
--- a/bitbake/lib/bb/cooker.py
+++ b/bitbake/lib/bb/cooker.py
@@ -1941,11 +1941,8 @@ class Parser(multiprocessing.Process):
                 result = pending.pop()
             else:
                 try:
-                    job = self.jobs.get(timeout=0.25)
-                except queue.Empty:
-                    continue
-
-                if job is None:
+                    job = self.jobs.pop()
+                except IndexError:
                     break
                 result = self.parse(*job)
 
@@ -2032,12 +2029,12 @@ class CookerParser(object):
             self.parser_quit = multiprocessing.Queue(maxsize=self.num_processes)
             self.result_queue = multiprocessing.Queue()
 
-            self.jobs = multiprocessing.Queue()
-            for j in self.willparse:
-                self.jobs.put(j)
+            def chunkify(lst,n):
+                return [lst[i::n] for i in range(n)]
+            self.jobs = chunkify(self.willparse, self.num_processes)
 
             for i in range(0, self.num_processes):
-                parser = Parser(self.jobs, self.result_queue, self.parser_quit, init, self.cooker.configuration.profile)
+                parser = Parser(self.jobs[i], self.result_queue, self.parser_quit, init, self.cooker.configuration.profile)
                 parser.start()
                 self.process_names.append(parser.name)
                 self.processes.append(parser)
@@ -2065,8 +2062,6 @@ class CookerParser(object):
             for process in self.processes:
                 self.parser_quit.put(None)
 
-            self.jobs.cancel_join_thread()
-
         for process in self.processes:
             if force:
                 process.join(.1)