rteval: Refactor collapse_cpulist in systopology

Instead of having duplicate code in two functions, one top-level and
one member function of CpuList, have only one static function in
CpuList.

Additionally re-write the implementation to use a more straight forward
one-pass algorithm.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: John Kacur <jkacur@redhat.com>

5 files changed, 30 insertions, 56 deletions

diff --git a/rteval-cmd b/rteval-cmd
index 6f613a3..7c41429 100755
--- a/rteval-cmd
+++ b/rteval-cmd
@@ -30,7 +30,7 @@ from rteval import RtEval, rtevalConfig
 from rteval.modules.loads import LoadModules
 from rteval.modules.measurement import MeasurementModules
 from rteval.version import RTEVAL_VERSION
-from rteval.systopology import CpuList, SysTopology, collapse_cpulist
+from rteval.systopology import CpuList, SysTopology
 from rteval.modules.loads.kcompile import ModuleParameters
 
 compress_cpulist = CpuList.compress_cpulist
@@ -211,7 +211,7 @@ def remove_offline(cpulist):
     """ return cpulist in collapsed compressed form with only online cpus """
     tmplist = expand_cpulist(cpulist)
     tmplist = SysTopology().online_cpulist(tmplist)
-    return collapse_cpulist(tmplist)
+    return CpuList.collapse_cpulist(tmplist)
 
 
 if __name__ == '__main__':
diff --git a/rteval/modules/loads/__init__.py b/rteval/modules/loads/__init__.py
index aca0c9f..13fba1e 100644
--- a/rteval/modules/loads/__init__.py
+++ b/rteval/modules/loads/__init__.py
@@ -11,7 +11,7 @@ import libxml2
 from rteval.Log import Log
 from rteval.rtevalConfig import rtevalCfgSection
 from rteval.modules import RtEvalModules, rtevalModulePrototype
-from rteval.systopology import collapse_cpulist, CpuList, SysTopology as SysTop
+from rteval.systopology import CpuList, SysTopology as SysTop
 
 class LoadThread(rtevalModulePrototype):
     def __init__(self, name, config, logger=None):
@@ -120,7 +120,7 @@ class LoadModules(RtEvalModules):
             cpulist = CpuList(cpulist).cpulist
         else:
             cpulist = SysTop().default_cpus()
-        rep_n.newProp("loadcpus", collapse_cpulist(cpulist))
+        rep_n.newProp("loadcpus", CpuList.collapse_cpulist(cpulist))
 
         return rep_n
 
diff --git a/rteval/modules/measurement/__init__.py b/rteval/modules/measurement/__init__.py
index 2a0556b..41b8022 100644
--- a/rteval/modules/measurement/__init__.py
+++ b/rteval/modules/measurement/__init__.py
@@ -5,7 +5,7 @@
 
 import libxml2
 from rteval.modules import RtEvalModules, ModuleContainer
-from rteval.systopology import collapse_cpulist, CpuList, SysTopology as SysTop
+from rteval.systopology import CpuList, SysTopology as SysTop
 
 class MeasurementProfile(RtEvalModules):
     """Keeps and controls all the measurement modules with the same measurement profile"""
@@ -187,7 +187,7 @@ measurement profiles, based on their characteristics"""
             cpulist = CpuList(cpulist).cpulist
         else:
             cpulist = SysTop().online_cpus() if run_on_isolcpus else SysTop().default_cpus()
-        rep_n.newProp("measurecpus", collapse_cpulist(cpulist))
+        rep_n.newProp("measurecpus", CpuList.collapse_cpulist(cpulist))
 
         for mp in self.__measureprofiles:
             mprep_n = mp.MakeReport()
diff --git a/rteval/modules/measurement/cyclictest.py b/rteval/modules/measurement/cyclictest.py
index 0af1d31..1b14e7e 100644
--- a/rteval/modules/measurement/cyclictest.py
+++ b/rteval/modules/measurement/cyclictest.py
@@ -17,7 +17,7 @@ import libxml2
 from rteval.Log import Log
 from rteval.modules import rtevalModulePrototype
 from rteval.systopology import cpuinfo
-from rteval.systopology import CpuList, SysTopology, collapse_cpulist
+from rteval.systopology import CpuList, SysTopology
 
 expand_cpulist = CpuList.expand_cpulist
 
@@ -203,7 +203,7 @@ class Cyclictest(rtevalModulePrototype):
             # Only include online cpus
             self.__cpus = CpuList(self.__cpus).cpulist
             # Reset cpulist from the newly calculated self.__cpus
-            self.__cpulist = collapse_cpulist(self.__cpus)
+            self.__cpulist = CpuList.collapse_cpulist(self.__cpus)
             self.__cpus = [str(c) for c in self.__cpus]
             self.__sparse = True
             if self.__run_on_isolcpus:
@@ -220,7 +220,7 @@ class Cyclictest(rtevalModulePrototype):
             self.__cpus = [c for c in self.__cpus if c in cpuset or self.__run_on_isolcpus and c in isolcpus]
             if self.__run_on_isolcpus:
                 self.__sparse = True
-                self.__cpulist = collapse_cpulist(self.__cpus)
+                self.__cpulist = CpuList.collapse_cpulist([int(c) for c in self.__cpus])
 
         # Sort the list of cpus to align with the order reported by cyclictest
         self.__cpus.sort(key=int)
diff --git a/rteval/systopology.py b/rteval/systopology.py
index 62ad355..ea8e242 100644
--- a/rteval/systopology.py
+++ b/rteval/systopology.py
@@ -10,25 +10,6 @@ import os
 import os.path
 import glob
 
-# Utility version of collapse_cpulist that doesn't require a CpuList object
-def collapse_cpulist(cpulist):
-    """ Collapse a list of cpu numbers into a string range
-        of cpus (e.g. 0-5, 7, 9) """
-    if len(cpulist) == 0:
-        return ""
-    idx = CpuList.longest_sequence(cpulist)
-    if idx == 0:
-        seq = str(cpulist[0])
-    else:
-        if idx == 1:
-            seq = f"{cpulist[0]},{cpulist[idx]}"
-        else:
-            seq = f"{cpulist[0]}-{cpulist[idx]}"
-
-    rest = collapse_cpulist(cpulist[idx+1:])
-    if rest == "":
-        return seq
-    return ",".join((seq, rest))
 
 def sysread(path, obj):
     """ Helper function for reading system files """
@@ -93,7 +74,7 @@ class CpuList:
         self.cpulist.sort()
 
     def __str__(self):
-        return self.__collapse_cpulist(self.cpulist)
+        return self.collapse_cpulist(self.cpulist)
 
     def __contains__(self, cpu):
         return cpu in self.cpulist
@@ -114,35 +95,28 @@ class CpuList:
         return os.path.exists(os.path.join(CpuList.cpupath, "isolated"))
 
     @staticmethod
-    def longest_sequence(cpulist):
-        """ return index of last element of a sequence that steps by one """
-        lim = len(cpulist)
-        for idx, _ in enumerate(cpulist):
-            if idx+1 == lim:
-                break
-            if int(cpulist[idx+1]) != (int(cpulist[idx])+1):
-                return idx
-        return lim - 1
-
-    def __collapse_cpulist(self, cpulist):
-        """ Collapse a list of cpu numbers into a string range
+    def collapse_cpulist(cpulist):
+        """
+        Collapse a list of cpu numbers into a string range
         of cpus (e.g. 0-5, 7, 9)
         """
-        if len(cpulist) == 0:
-            return ""
-        idx = self.longest_sequence(cpulist)
-        if idx == 0:
-            seq = str(cpulist[0])
-        else:
-            if idx == 1:
-                seq = f"{cpulist[0]},{cpulist[idx]}"
+        cur_range = [None, None]
+        result = []
+        for cpu in cpulist + [None]:
+            if cur_range[0] is None:
+                cur_range[0] = cur_range[1] = cpu
+                continue
+            if cpu is not None and cpu == cur_range[1] + 1:
+                # Extend currently processed range
+                cur_range[1] += 1
             else:
-                seq = f"{cpulist[0]}-{cpulist[idx]}"
-
-        rest = self.__collapse_cpulist(cpulist[idx+1:])
-        if rest == "":
-            return seq
-        return ",".join((seq, rest))
+                # Range processing finished, add range to string
+                result.append(f"{cur_range[0]}-{cur_range[1]}"
+                              if cur_range[0] != cur_range[1]
+                              else str(cur_range[0]))
+                # Reset
+                cur_range[0] = cur_range[1] = cpu
+        return ",".join(result)
 
     @staticmethod
     def compress_cpulist(cpulist):
@@ -428,7 +402,7 @@ if __name__ == "__main__":
 
         onlcpus = s.online_cpus()
         print(f'onlcpus = {onlcpus}')
-        onlcpus = collapse_cpulist(onlcpus)
+        onlcpus = CpuList.collapse_cpulist(onlcpus)
         print(f'onlcpus = {onlcpus}')
 
         onlcpus_str = s.online_cpus_str()