runqueue: Optimise task id string manipulations

Some task id manipulations were suboptimal:

* taskfn_fromtid and fn_from_tid were effectively the same function
* many calls to split_tid(), then taskfn_fromtid()
* taskfn_fromtid() called split_tid() internally

This patch adds split_tid_mcfn() to replace split_tid() and returns the "taskfn" variant being used in many places. We update all core calls to the new function and ignore the return values we don't need since the function call overhead of the split_tid wrapper is higher than ignoring a return value.

The one remaining standalone use of taskfn_fromtid is replaced with fn_from_tid. I couldn't see any external usage so it was dropped.

There is external usage of split_tid so a wrapper remains for it.

Combined together these changes should improve some of the runqueue task manipulation performance.

index 934072c..42831e2 100644
@@ -748,8 +748,7 @@ class BBCooker:

                     depend_tree['providermap'][name] = (pn, version)

         for tid in rq.rqdata.runtaskentries:
-            (mc, fn, taskname) = bb.runqueue.split_tid(tid)
-            taskfn = bb.runqueue.taskfn_fromtid(tid)
+            (mc, fn, taskname, taskfn) = bb.runqueue.split_tid_mcfn(tid) pn = self.recipecaches[mc].pkg_fn[taskfn]
             pn = self.add_mc_prefix(mc, pn)
             version  = "%s:%s-%s" % self.recipecaches[mc].pkg_pepvpr[taskfn] @@ -772,8 +771,7 @@ class BBCooker:


             for dep in rq.rqdata.runtaskentries[tid].depends:
-                (depmc, depfn, deptaskname) = bb.runqueue.split_tid(dep)
-                deptaskfn = bb.runqueue.taskfn_fromtid(dep)
+                (depmc, depfn, deptaskname, deptaskfn) = bb.runqueue.split_tid_mcfn(dep) deppn = self.recipecaches[mc].pkg_fn[deptaskfn]
                 dotname = "%s.%s" % (pn, bb.runqueue.taskname_from_tid(tid)) if not dotname in depend_tree["tdepends"]:
@@ -843,8 +841,7 @@ class BBCooker:
                 tids.append(tid)

         for tid in tids:
-            (mc, fn, taskname) = bb.runqueue.split_tid(tid)
-            taskfn = bb.runqueue.taskfn_fromtid(tid)
+            (mc, fn, taskname, taskfn) = bb.runqueue.split_tid_mcfn(tid)

             pn = self.recipecaches[mc].pkg_fn[taskfn]
             pn = self.add_mc_prefix(mc, pn)

index 0483b95..3b674ba 100644
@@ -49,30 +49,30 @@ def taskname_from_tid(tid):

     return tid.rsplit(":", 1)[1]

 def split_tid(tid):
+    (mc, fn, taskname, _) = split_tid_mcfn(tid)
+    return (mc, fn, taskname)
+
+def split_tid_mcfn(tid):
     if tid.startswith('multiconfig:'):
         elems = tid.split(':')
         mc = elems[1]
         fn = ":".join(elems[2:-1])
         taskname = elems[-1]
+        mcfn = "multiconfig:" + mc + ":" + fn
     else:
         tid = tid.rsplit(":", 1)
         mc = ""
         fn = tid[0]
         taskname = tid[1]
+        mcfn = fn

-    return (mc, fn, taskname)
+    return (mc, fn, taskname, mcfn)

 def build_tid(mc, fn, taskname):
     if mc:
         return "multiconfig:" + mc + ":" + fn + ":" + taskname
     return fn + ":" + taskname

-def taskfn_fromtid(tid):
-    (mc, fn, taskname) = split_tid(tid)
-    if mc:
-        return "multiconfig:" + mc + ":" + fn
-    return fn
-
 class RunQueueStats:
     """
     Holds statistics on the tasks handled by the associated runQueue
@@ -135,8 +135,7 @@ class RunQueueScheduler(object):
         self.buildable = []
         self.stamps = {}
         for tid in self.rqdata.runtaskentries:
-            (mc, fn, taskname) = split_tid(tid)
-            taskfn = taskfn_fromtid(tid)
+            (mc, fn, taskname, taskfn) = split_tid_mcfn(tid)
             self.stamps[tid] = bb.build.stampfile(taskname, self.rqdata.dataCaches[mc], taskfn, noextra=True) if tid in self.rq.runq_buildable:
                 self.buildable.append(tid)
@@ -289,7 +288,7 @@ class RunQueueData:
         return tid + task_name_suffix

     def get_short_user_idstring(self, task, task_name_suffix = ""):
-        (mc, fn, taskname) = split_tid(task)
+        (mc, fn, taskname, _) = split_tid_mcfn(task)
         pn = self.dataCaches[mc].pkg_fn[fn]
         taskname = taskname_from_tid(task) + task_name_suffix
         return "%s:%s" % (pn, taskname)
@@ -511,9 +510,8 @@ class RunQueueData:
         for mc in taskData:
             for tid in taskData[mc].taskentries:

-                (mc, fn, taskname) = split_tid(tid)
+                (mc, fn, taskname, taskfn) = split_tid_mcfn(tid)
                 #runtid = build_tid(mc, fn, taskname)
-                taskfn = taskfn_fromtid(tid)

                 #logger.debug(2, "Processing %s,%s:%s", mc, fn, taskname)

@@ -529,7 +527,7 @@ class RunQueueData:
                 #

                 # e.g. addtask before X after Y
                 for t in taskData[mc].taskentries[tid].tdepends:
-                    (_, depfn, deptaskname) = split_tid(t)
+                    (_, depfn, deptaskname, _) = split_tid_mcfn(t)
                     depends.add(build_tid(mc, depfn, deptaskname))
 
                 # Resolve 'deptask' dependencies
@@ -611,7 +609,7 @@ class RunQueueData:
 
             def generate_recdeps(t):
                 newdeps = set()
-                (mc, fn, taskname) = split_tid(t)
+                (mc, fn, taskname, _) = split_tid_mcfn(t)
                 add_resolved_dependencies(mc, fn, tasknames, newdeps)
                 extradeps[tid].update(newdeps)
                 seendeps.add(t)
@@ -774,8 +772,7 @@ class RunQueueData:
             prov_list = {}
             seen_fn = []
             for tid in self.runtaskentries:
-                (tidmc, fn, taskname) = split_tid(tid)
-                taskfn = taskfn_fromtid(tid)
+                (tidmc, fn, taskname, taskfn) = split_tid_mcfn(tid)
                 if taskfn in seen_fn:
                     continue
                 if mc != tidmc:
@@ -885,14 +882,14 @@ class RunQueueData:
         self.runq_setscene_tids = []
         if not self.cooker.configuration.nosetscene:
             for tid in self.runtaskentries:
-                (mc, fn, taskname) = split_tid(tid)
+                (mc, fn, taskname, _) = split_tid_mcfn(tid)
                 setscenetid = fn + ":" + taskname + "_setscene"
                 if setscenetid not in taskData[mc].taskentries:
                     continue
                 self.runq_setscene_tids.append(tid)
 
         def invalidate_task(tid, error_nostamp):
-            (mc, fn, taskname) = split_tid(tid)
+            (mc, fn, taskname, _) = split_tid_mcfn(tid)
             taskdep = self.dataCaches[mc].task_deps[fn]
             if fn + ":" + taskname not in taskData[mc].taskentries:
                 logger.warning("Task %s does not exist, invalidating this task will have no effect" % taskname)
@@ -946,8 +943,7 @@ class RunQueueData:
                     procdep = []
                     for dep in self.runtaskentries[tid].depends:
                         procdep.append(fn_from_tid(dep) + "." + taskname_from_tid(dep))
-                    (mc, fn, taskname) = split_tid(tid)
-                    taskfn = taskfn_fromtid(tid)
+                    (mc, fn, taskname, taskfn) = split_tid_mcfn(tid)
                     self.runtaskentries[tid].hash = bb.parse.siggen.get_taskhash(taskfn, taskname, procdep, self.dataCaches[mc])
                     task = self.runtaskentries[tid].task
 
@@ -1099,8 +1095,7 @@ class RunQueue:
             except:
                 return None
 
-        (mc, fn, tn) = split_tid(tid)
-        taskfn = taskfn_fromtid(tid)
+        (mc, fn, tn, taskfn) = split_tid_mcfn(tid)
         if taskname is None:
             taskname = tn
 
@@ -1134,8 +1129,7 @@ class RunQueue:
         t1 = get_timestamp(stampfile)
         for dep in self.rqdata.runtaskentries[tid].depends:
             if iscurrent:
-                (mc2, fn2, taskname2) = split_tid(dep)
-                taskfn2 = taskfn_fromtid(dep)
+                (mc2, fn2, taskname2, taskfn2) = split_tid_mcfn(dep)
                 stampfile2 = bb.build.stampfile(taskname2, self.rqdata.dataCaches[mc2], taskfn2)
                 stampfile3 = bb.build.stampfile(taskname2 + "_setscene", self.rqdata.dataCaches[mc2], taskfn2)
                 t2 = get_timestamp(stampfile2)
@@ -1247,7 +1241,7 @@ class RunQueue:
             if not self.rqdata.taskData[''].tryaltconfigs:
                 raise bb.runqueue.TaskFailure(self.rqexe.failed_tids)
             for tid in self.rqexe.failed_tids:
-                (mc, fn, tn) = split_tid(tid)
+                (mc, fn, tn, _) = split_tid_mcfn(tid)
                 self.rqdata.taskData[mc].fail_fn(fn)
             self.rqdata.reset()
 
@@ -1297,7 +1291,7 @@ class RunQueue:
         bb.note("Reparsing files to collect dependency data")
         bb_cache = bb.cache.NoCache(self.cooker.databuilder)
         for tid in self.rqdata.runtaskentries:
-            fn = taskfn_fromtid(tid)
+            fn = fn_from_tid(tid)
             if fn not in done:
                 the_data = bb_cache.loadDataFull(fn, self.cooker.collection.get_file_appends(fn))
                 done.add(fn)
@@ -1319,8 +1313,7 @@ class RunQueue:
         valid_new = set()
 
         for tid in self.rqdata.runtaskentries:
-            (mc, fn, taskname) = split_tid(tid)
-            taskfn = taskfn_fromtid(tid)
+            (mc, fn, taskname, taskfn) = split_tid_mcfn(tid)
             taskdep = self.rqdata.dataCaches[mc].task_deps[taskfn]
 
             if 'noexec' in taskdep and taskname in taskdep['noexec']:
@@ -1408,7 +1401,7 @@ class RunQueue:
 
 
         for tid in invalidtasks:
-            (mc, fn, taskname) = split_tid(tid)
+            (mc, fn, taskname, _) = split_tid_mcfn(tid)
             pn = self.rqdata.dataCaches[mc].pkg_fn[fn]
             h = self.rqdata.runtaskentries[tid].hash
             matches = bb.siggen.find_siginfo(pn, taskname, [], self.cfgData)
@@ -1512,7 +1505,7 @@ class RunQueueExecute:
         taskdata = {}
         taskdeps.add(task)
         for dep in taskdeps:
-            (mc, fn, taskname) = split_tid(dep)
+            (mc, fn, taskname, _) = split_tid_mcfn(dep)
             pn = self.rqdata.dataCaches[mc].pkg_fn[fn]
             taskdata[dep] = [pn, taskname, fn]
         call = self.rq.depvalidate + "(task, taskdata, notneeded, d)"
@@ -1569,8 +1562,7 @@ class RunQueueExecuteTasks(RunQueueExecute):
             tasknames = {}
             fns = {}
             for tid in self.rqdata.runtaskentries:
-                (mc, fn, taskname) = split_tid(tid)
-                taskfn = taskfn_fromtid(tid)
+                (mc, fn, taskname, taskfn) = split_tid_mcfn(tid)
                 taskdep = self.rqdata.dataCaches[mc].task_deps[taskfn]
                 fns[tid] = taskfn
                 tasknames[tid] = taskname
@@ -1589,9 +1581,8 @@ class RunQueueExecuteTasks(RunQueueExecute):
             covered_remove = bb.utils.better_eval(call, locs)
 
         def removecoveredtask(tid):
-            (mc, fn, taskname) = split_tid(tid)
+            (mc, fn, taskname, taskfn) = split_tid_mcfn(tid)
             taskname = taskname + '_setscene'
-            taskfn = taskfn_fromtid(tid)
             bb.build.del_stamp(taskname, self.rqdata.dataCaches[mc], taskfn)
             self.rq.scenequeue_covered.remove(tid)
 
@@ -1617,7 +1608,7 @@ class RunQueueExecuteTasks(RunQueueExecute):
         for mc in self.rqdata.dataCaches:
             target_pairs = []
             for tid in self.rqdata.target_tids:
-                (tidmc, fn, taskname) = split_tid(tid)
+                (tidmc, fn, taskname, _) = split_tid_mcfn(tid)
                 if tidmc == mc:
                     target_pairs.append((fn, taskname))
 
@@ -1713,7 +1704,7 @@ class RunQueueExecuteTasks(RunQueueExecute):
         if self.rqdata.setscenewhitelist:
             # Check tasks that are going to run against the whitelist
             def check_norun_task(tid, showerror=False):
-                (mc, fn, taskname) = split_tid(tid)
+                (mc, fn, taskname, _) = split_tid_mcfn(tid)
                 # Ignore covered tasks
                 if tid in self.rq.scenequeue_covered:
                     return False
@@ -1761,8 +1752,7 @@ class RunQueueExecuteTasks(RunQueueExecute):
 
         task = self.sched.next()
         if task is not None:
-            (mc, fn, taskname) = split_tid(task)
-            taskfn = taskfn_fromtid(task)
+            (mc, fn, taskname, taskfn) = split_tid_mcfn(task)
 
             if task in self.rq.scenequeue_covered:
                 logger.debug(2, "Setscene covered task %s", task)
@@ -1842,8 +1832,7 @@ class RunQueueExecuteTasks(RunQueueExecute):
         while next:
             additional = []
             for revdep in next:
-                (mc, fn, taskname) = split_tid(revdep)
-                taskfn = taskfn_fromtid(revdep)
+                (mc, fn, taskname, taskfn) = split_tid_mcfn(revdep)
                 pn = self.rqdata.dataCaches[mc].pkg_fn[taskfn]
                 deps = self.rqdata.runtaskentries[revdep].depends
                 provides = self.rqdata.dataCaches[mc].fn_provides[taskfn]
@@ -1999,7 +1988,7 @@ class RunQueueExecuteScenequeue(RunQueueExecute):
         # e.g. do_sometask_setscene[depends] = "targetname:do_someothertask_setscene"
         # Note that anything explicitly depended upon will have its reverse dependencies removed to avoid circular dependencies
         for tid in self.rqdata.runq_setscene_tids:
-                (mc, fn, taskname) = split_tid(tid)
+                (mc, fn, taskname, _) = split_tid_mcfn(tid)
                 realtid = fn + ":" + taskname + "_setscene"
                 idepends = self.rqdata.taskData[mc].taskentries[realtid].idepends
                 for (depname, idependtask) in idepends:
@@ -2063,8 +2052,7 @@ class RunQueueExecuteScenequeue(RunQueueExecute):
             noexec = []
             stamppresent = []
             for tid in self.sq_revdeps:
-                (mc, fn, taskname) = split_tid(tid)
-                taskfn = taskfn_fromtid(tid)
+                (mc, fn, taskname, taskfn) = split_tid_mcfn(tid)
 
                 taskdep = self.rqdata.dataCaches[mc].task_deps[fn]
 
@@ -2135,7 +2123,7 @@ class RunQueueExecuteScenequeue(RunQueueExecute):
     def check_taskfail(self, task):
         if self.rqdata.setscenewhitelist:
             realtask = task.split('_setscene')[0]
-            (mc, fn, taskname) = split_tid(realtask)
+            (mc, fn, taskname, _) = split_tid_mcfn(realtask)
             pn = self.rqdata.dataCaches[mc].pkg_fn[fn]
             if not check_setscene_enforce_whitelist(pn, taskname, self.rqdata.setscenewhitelist):
                 logger.error('Task %s.%s failed' % (pn, taskname + "_setscene"))
@@ -2199,8 +2187,7 @@ class RunQueueExecuteScenequeue(RunQueueExecute):
                     task = nexttask
                     break
         if task is not None:
-            (mc, fn, taskname) = split_tid(task)
-            taskfn = taskfn_fromtid(task)
+            (mc, fn, taskname, taskfn) = split_tid_mcfn(task)
             taskname = taskname + "_setscene"
             if self.rq.check_stamp_task(task, taskname_from_tid(task), recurse = True, cache=self.stampcache):
                 logger.debug(2, 'Stamp for underlying task %s is current, so skipping setscene variant', task)

Thanks Richard. As per our discussion on IRC yesterday these changes are inline with what I was expecting. After sorting out the encoding on this email to get the patch applied I was able to confirm that we do get some performance improvements. For my specific test configuration of ~4500 tasks I am seeing > 1 second performance improvement and 1/2million less function calls. (when not profiling that will be 1/2second improvement since profiling is doubling my runtime). With the cleanup of taskfn_fromtid and fn_from_tid I will be able to put together some additional performance improvement patches and send them out for discussion in the next few days.

Thanks again,
Mark