bitbake: lib/bb: Fix string concatination potential performance issues

Python scales badly when concatinating strings in loops. Most of these
references aren't problematic but at least one (in data.py) is probably
a performance issue as the issue is compounded as strings become large.

The way to handle this in python is to create lists which don't reconstruct
all the objects when appending to them. We may as well fix all the references
since it stops them being copy/pasted into something problematic in the future.

This patch was based on issues highligthted by a report from AWS Codeguru.

(Bitbake rev: d654139a833127b16274dca0ccbbab7e3bb33ed0)

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

1 files changed, 19 insertions, 18 deletions

diff --git a/bitbake/lib/bb/runqueue.py b/bitbake/lib/bb/runqueue.py
index 87c00462c1..774cdbca0b 100644
--- a/bitbake/lib/bb/runqueue.py
+++ b/bitbake/lib/bb/runqueue.py
@@ -1061,12 +1061,12 @@ class RunQueueData:
                         seen_pn.append(pn)
                     else:
                         bb.fatal("Multiple versions of %s are due to be built (%s). Only one version of a given PN should be built in any given build. You likely need to set PREFERRED_VERSION_%s to select the correct version or don't depend on multiple versions." % (pn, " ".join(prov_list[prov]), pn))
-                msg = "Multiple .bb files are due to be built which each provide %s:\n  %s" % (prov, "\n  ".join(prov_list[prov]))
+                msgs = ["Multiple .bb files are due to be built which each provide %s:\n  %s" % (prov, "\n  ".join(prov_list[prov]))]
                 #
                 # Construct a list of things which uniquely depend on each provider
                 # since this may help the user figure out which dependency is triggering this warning
                 #
-                msg += "\nA list of tasks depending on these providers is shown and may help explain where the dependency comes from."
+                msgs.append("\nA list of tasks depending on these providers is shown and may help explain where the dependency comes from.")
                 deplist = {}
                 commondeps = None
                 for provfn in prov_list[prov]:
@@ -1086,12 +1086,12 @@ class RunQueueData:
                         commondeps &= deps
                     deplist[provfn] = deps
                 for provfn in deplist:
-                    msg += "\n%s has unique dependees:\n  %s" % (provfn, "\n  ".join(deplist[provfn] - commondeps))
+                    msgs.append("\n%s has unique dependees:\n  %s" % (provfn, "\n  ".join(deplist[provfn] - commondeps)))
                 #
                 # Construct a list of provides and runtime providers for each recipe
                 # (rprovides has to cover RPROVIDES, PACKAGES, PACKAGES_DYNAMIC)
                 #
-                msg += "\nIt could be that one recipe provides something the other doesn't and should. The following provider and runtime provider differences may be helpful."
+                msgs.append("\nIt could be that one recipe provides something the other doesn't and should. The following provider and runtime provider differences may be helpful.")
                 provide_results = {}
                 rprovide_results = {}
                 commonprovs = None
@@ -1118,16 +1118,16 @@ class RunQueueData:
                     else:
                         commonrprovs &= rprovides
                     rprovide_results[provfn] = rprovides
-                #msg += "\nCommon provides:\n  %s" % ("\n  ".join(commonprovs))
-                #msg += "\nCommon rprovides:\n  %s" % ("\n  ".join(commonrprovs))
+                #msgs.append("\nCommon provides:\n  %s" % ("\n  ".join(commonprovs)))
+                #msgs.append("\nCommon rprovides:\n  %s" % ("\n  ".join(commonrprovs)))
                 for provfn in prov_list[prov]:
-                    msg += "\n%s has unique provides:\n  %s" % (provfn, "\n  ".join(provide_results[provfn] - commonprovs))
-                    msg += "\n%s has unique rprovides:\n  %s" % (provfn, "\n  ".join(rprovide_results[provfn] - commonrprovs))
+                    msgs.append("\n%s has unique provides:\n  %s" % (provfn, "\n  ".join(provide_results[provfn] - commonprovs)))
+                    msgs.append("\n%s has unique rprovides:\n  %s" % (provfn, "\n  ".join(rprovide_results[provfn] - commonrprovs)))
 
                 if self.warn_multi_bb:
-                    logger.verbnote(msg)
+                    logger.verbnote("".join(msgs))
                 else:
-                    logger.error(msg)
+                    logger.error("".join(msgs))
 
         self.init_progress_reporter.next_stage()
 
@@ -1935,7 +1935,7 @@ class RunQueueExecute:
         self.stats.taskFailed()
         self.failed_tids.append(task)
 
-        fakeroot_log = ""
+        fakeroot_log = []
         if fakerootlog and os.path.exists(fakerootlog):
             with open(fakerootlog) as fakeroot_log_file:
                 fakeroot_failed = False
@@ -1945,12 +1945,12 @@ class RunQueueExecute:
                             fakeroot_failed = True
                     if 'doing new pid setup and server start' in line:
                         break
-                    fakeroot_log = line + fakeroot_log
+                    fakeroot_log.append(line)
 
             if not fakeroot_failed:
-                fakeroot_log = None
+                fakeroot_log = []
 
-        bb.event.fire(runQueueTaskFailed(task, self.stats, exitcode, self.rq, fakeroot_log=fakeroot_log), self.cfgData)
+        bb.event.fire(runQueueTaskFailed(task, self.stats, exitcode, self.rq, fakeroot_log=("".join(fakeroot_log) or None)), self.cfgData)
 
         if self.rqdata.taskData[''].abort:
             self.rq.state = runQueueCleanUp
@@ -2608,12 +2608,13 @@ class RunQueueExecute:
         pn = self.rqdata.dataCaches[mc].pkg_fn[taskfn]
         if not check_setscene_enforce_whitelist(pn, taskname, self.rqdata.setscenewhitelist):
             if tid in self.rqdata.runq_setscene_tids:
-                msg = 'Task %s.%s attempted to execute unexpectedly and should have been setscened' % (pn, taskname)
+                msg = ['Task %s.%s attempted to execute unexpectedly and should have been setscened' % (pn, taskname)]
             else:
-                msg = 'Task %s.%s attempted to execute unexpectedly' % (pn, taskname)
+                msg = ['Task %s.%s attempted to execute unexpectedly' % (pn, taskname)]
             for t in self.scenequeue_notcovered:
-                msg = msg + "\nTask %s, unihash %s, taskhash %s" % (t, self.rqdata.runtaskentries[t].unihash, self.rqdata.runtaskentries[t].hash)
-            logger.error(msg + '\nThis is usually due to missing setscene tasks. Those missing in this build were: %s' % pprint.pformat(self.scenequeue_notcovered))
+                msg.append("\nTask %s, unihash %s, taskhash %s" % (t, self.rqdata.runtaskentries[t].unihash, self.rqdata.runtaskentries[t].hash))
+            msg.append('\nThis is usually due to missing setscene tasks. Those missing in this build were: %s' % pprint.pformat(self.scenequeue_notcovered))
+            logger.error("".join(msg))
             return True
         return False