diff --git a/tools/perf/tests/shell/lib/perf_metric_validation.py b/tools/perf/tests/shell/lib/perf_metric_validation.py
index 3c3a9b4f8b82..50a34a9cc040 100644
--- a/tools/perf/tests/shell/lib/perf_metric_validation.py
+++ b/tools/perf/tests/shell/lib/perf_metric_validation.py
@@ -11,8 +11,9 @@ class Validator:
         self.rulefname = rulefname
         self.reportfname = reportfname
         self.rules = None
-        self.collectlist=metrics
-        self.metrics = set(metrics)
+        self.collectlist:str = metrics
+        self.metrics = self.__set_metrics(metrics)
+        self.skiplist = set()
         self.tolerance = t
 
         self.workloads = [x for x in workload.split(",") if x]
@@ -41,6 +42,12 @@ class Validator:
         self.debug = debug
         self.fullrulefname = fullrulefname
 
+    def __set_metrics(self, metrics=''):
+        if metrics != '':
+            return set(metrics.split(","))
+        else:
+            return set()
+
     def read_json(self, filename: str) -> dict:
         try:
             with open(Path(filename).resolve(), "r") as f:
@@ -113,7 +120,7 @@ class Validator:
         All future test(s) on this metric will fail.
 
         @param name: name of the metric
-        @returns: list with value found in self.results; list is empty when not value found.
+        @returns: list with value found in self.results; list is empty when value is not found.
         """
         results = []
         data = self.results[ridx] if ridx in self.results else self.results[0]
@@ -123,7 +130,6 @@ class Validator:
             elif name.replace('.', '1').isdigit():
                 results.append(float(name))
             else:
-                self.errlist.append("Metric '%s' is not collected or the value format is incorrect"%(name))
                 self.ignoremetrics.add(name)
         return results
 
@@ -138,27 +144,32 @@ class Validator:
         Failure: when metric value is negative or not provided.
         Metrics with negative value will be added into the self.failtests['PositiveValueTest'] and self.ignoremetrics.
         """
-        negmetric = set()
-        missmetric = set()
+        negmetric = dict()
         pcnt = 0
         tcnt = 0
+        rerun = list()
         for name, val in self.get_results().items():
-            if val is None or val == '':
-                missmetric.add(name)
-                self.errlist.append("Metric '%s' is not collected"%(name))
-            elif val < 0:
-                negmetric.add("{0}(={1:.4f})".format(name, val))
-                self.collectlist[0].append(name)
+            if val < 0:
+                negmetric[name] = val
+                rerun.append(name)
             else:
                 pcnt += 1
             tcnt += 1
+        if len(rerun) > 0 and len(rerun) < 20:
+            second_results = dict()
+            self.second_test(rerun, second_results)
+            for name, val in second_results.items():
+                if name not in negmetric: continue
+                if val >= 0:
+                    del negmetric[name]
+                    pcnt += 1
 
         self.failtests['PositiveValueTest']['Total Tests'] = tcnt
         self.failtests['PositiveValueTest']['Passed Tests'] = pcnt
-        if len(negmetric) or len(missmetric)> 0:
-            self.ignoremetrics.update(negmetric)
-            self.ignoremetrics.update(missmetric)
-            self.failtests['PositiveValueTest']['Failed Tests'].append({'NegativeValue':list(negmetric), 'MissingValue':list(missmetric)})
+        if len(negmetric.keys()):
+            self.ignoremetrics.update(negmetric.keys())
+            negmessage = ["{0}(={1:.4f})".format(name, val) for name, val in negmetric.items()]
+            self.failtests['PositiveValueTest']['Failed Tests'].append({'NegativeValue': negmessage})
 
         return
 
@@ -259,21 +270,36 @@ class Validator:
         metrics = rule['Metrics']
         passcnt = 0
         totalcnt = 0
-        faillist = []
+        faillist = list()
+        failures = dict()
+        rerun = list()
         for m in metrics:
             totalcnt += 1
             result = self.get_value(m['Name'])
-            if len(result) > 0 and self.check_bound(result[0], lbv, ubv, t):
+            if len(result) > 0 and self.check_bound(result[0], lbv, ubv, t) or m['Name'] in self.skiplist:
                 passcnt += 1
             else:
-                faillist.append({'MetricName':m['Name'], 'CollectedValue':result})
-                self.collectlist[0].append(m['Name'])
+                failures[m['Name']] = result
+                rerun.append(m['Name'])
+
+        if len(rerun) > 0 and len(rerun) < 20:
+            second_results = dict()
+            self.second_test(rerun, second_results)
+            for name, val in second_results.items():
+                if name not in failures: continue
+                if self.check_bound(val, lbv, ubv, t):
+                    passcnt += 1
+                    del failures[name]
+                else:
+                    failures[name] = val
+                    self.results[0][name] = val
 
         self.totalcnt += totalcnt
         self.passedcnt += passcnt
         self.failtests['SingleMetricTest']['Total Tests'] += totalcnt
         self.failtests['SingleMetricTest']['Passed Tests'] += passcnt
-        if len(faillist) != 0:
+        if len(failures.keys()) != 0:
+            faillist = [{'MetricName':name, 'CollectedValue':val} for name, val in failures.items()]
             self.failtests['SingleMetricTest']['Failed Tests'].append({'RuleIndex':rule['RuleIndex'],
                                                                        'RangeLower': rule['RangeLower'],
                                                                        'RangeUpper': rule['RangeUpper'],
@@ -316,7 +342,7 @@ class Validator:
         return True
 
     # Start of Collector and Converter
-    def convert(self, data: list, idx: int):
+    def convert(self, data: list, metricvalues:dict):
         """
         Convert collected metric data from the -j output to dict of {metric_name:value}.
         """
@@ -326,20 +352,29 @@ class Validator:
                 if "metric-unit" in result and result["metric-unit"] != "(null)" and result["metric-unit"] != "":
                     name = result["metric-unit"].split("  ")[1] if len(result["metric-unit"].split("  ")) > 1 \
                         else result["metric-unit"]
-                    if idx not in self.results: self.results[idx] = dict()
-                    self.results[idx][name.lower()] = float(result["metric-value"])
+                    metricvalues[name.lower()] = float(result["metric-value"])
             except ValueError as error:
                 continue
         return
 
-    def collect_perf(self, data_file: str, workload: str):
+    def _run_perf(self, metric, workload: str):
+        tool = 'perf'
+        command = [tool, 'stat', '-j', '-M', f"{metric}", "-a"]
+        wl = workload.split()
+        command.extend(wl)
+        print(" ".join(command))
+        cmd = subprocess.run(command, stderr=subprocess.PIPE, encoding='utf-8')
+        data = [x+'}' for x in cmd.stderr.split('}\n') if x]
+        return data
+
+
+    def collect_perf(self, workload: str):
         """
         Collect metric data with "perf stat -M" on given workload with -a and -j.
         """
         self.results = dict()
-        tool = 'perf'
         print(f"Starting perf collection")
-        print(f"Workload: {workload}")
+        print(f"Long workload: {workload}")
         collectlist = dict()
         if self.collectlist != "":
             collectlist[0] = {x for x in self.collectlist.split(",")}
@@ -353,17 +388,20 @@ class Validator:
                     collectlist[rule["RuleIndex"]] = [",".join(list(set(metrics)))]
 
         for idx, metrics in collectlist.items():
-            if idx == 0: wl = "sleep 0.5".split()
-            else: wl = workload.split()
+            if idx == 0: wl = "true"
+            else: wl = workload
             for metric in metrics:
-                command = [tool, 'stat', '-j', '-M', f"{metric}", "-a"]
-                command.extend(wl)
-                print(" ".join(command))
-                cmd = subprocess.run(command, stderr=subprocess.PIPE, encoding='utf-8')
-                data = [x+'}' for x in cmd.stderr.split('}\n') if x]
-                self.convert(data, idx)
-        self.collectlist = dict()
-        self.collectlist[0] = list()
+                data = self._run_perf(metric, wl)
+                if idx not in self.results: self.results[idx] = dict()
+                self.convert(data, self.results[idx])
+        return
+
+    def second_test(self, collectlist, second_results):
+        workload = self.workloads[self.wlidx]
+        for metric in collectlist:
+            data = self._run_perf(metric, workload)
+            self.convert(data, second_results)
+
     # End of Collector and Converter
 
     # Start of Rule Generator
@@ -381,7 +419,7 @@ class Validator:
                 if 'MetricName' not in m:
                     print("Warning: no metric name")
                     continue
-                name = m['MetricName']
+                name = m['MetricName'].lower()
                 self.metrics.add(name)
                 if 'ScaleUnit' in m and (m['ScaleUnit'] == '1%' or m['ScaleUnit'] == '100%'):
                     self.pctgmetrics.add(name.lower())
@@ -391,14 +429,12 @@ class Validator:
 
         return
 
-    def remove_unsupported_rules(self, rules, skiplist: set = None):
-        for m in skiplist:
-            self.metrics.discard(m)
+    def remove_unsupported_rules(self, rules):
         new_rules = []
         for rule in rules:
             add_rule = True
             for m in rule["Metrics"]:
-                if m["Name"] not in self.metrics:
+                if m["Name"] in self.skiplist or m["Name"] not in self.metrics:
                     add_rule = False
                     break
             if add_rule:
@@ -415,15 +451,15 @@ class Validator:
         """
         data = self.read_json(self.rulefname)
         rules = data['RelationshipRules']
-        skiplist = set(data['SkipList'])
-        self.rules = self.remove_unsupported_rules(rules, skiplist)
+        self.skiplist = set([name.lower() for name in data['SkipList']])
+        self.rules = self.remove_unsupported_rules(rules)
         pctgrule = {'RuleIndex':0,
                     'TestType':'SingleMetricTest',
                     'RangeLower':'0',
                     'RangeUpper': '100',
                     'ErrorThreshold': self.tolerance,
                     'Description':'Metrics in percent unit have value with in [0, 100]',
-                    'Metrics': [{'Name': m} for m in self.pctgmetrics]}
+                    'Metrics': [{'Name': m.lower()} for m in self.pctgmetrics]}
         self.rules.append(pctgrule)
 
         # Re-index all rules to avoid repeated RuleIndex
@@ -479,8 +515,9 @@ class Validator:
             self.parse_perf_metrics()
         self.create_rules()
         for i in range(0, len(self.workloads)):
+            self.wlidx = i
             self._init_data()
-            self.collect_perf(self.datafname, self.workloads[i])
+            self.collect_perf(self.workloads[i])
             # Run positive value test
             self.pos_val_test()
             for r in self.rules: