From 8f6e9a172923b67ccffaf9fd519642ae242db868 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fl.fischer@fau.de>
Date: Tue, 24 Jul 2018 11:17:48 +0200
Subject: add falsesharing benchmarks from berger

---
 falsesharing.py | 124 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 falsesharing.py

(limited to 'falsesharing.py')

diff --git a/falsesharing.py b/falsesharing.py
new file mode 100644
index 0000000..627acc0
--- /dev/null
+++ b/falsesharing.py
@@ -0,0 +1,124 @@
+import csv
+import pickle
+import matplotlib.pyplot as plt
+import multiprocessing
+import numpy as np
+import os
+import re
+import subprocess
+
+from benchmark import Benchmark
+from common_targets import common_targets
+
+cmd = ("perf stat -x\; -e cpu-clock:k,cache-references,cache-misses,cycles,"
+       "instructions,branches,faults,migrations "
+       "build/cache-{}{} {} 100 8 1000000")
+
+class Benchmark_Falsesharing( Benchmark ):
+    def __init__(self):
+        self.name = "falsesharing"
+        self.descrition = """This benchmarks makes small allocations and writes
+                            to them multiple times. If the allocated objects are
+                            on the same cache line the writes will be expensive because
+                            of cache trashing.""",
+        self.targets = common_targets
+        self.nthreads = range(1, multiprocessing.cpu_count() * 2 + 1)
+
+        self.results = {"args" : {"nthreads" : self.nthreads},
+                        "targets" : self.targets,
+                        "thrash": {},
+                        "scratch": {}}
+
+    def prepare(self, verbose=False):
+        req = ["build/cache-thrash", "build/cache-scratch"]
+        for r in req:
+            if not os.path.isfile(r):
+                print(r, "not found")
+                return False
+            if not os.access(r, os.X_OK):
+                print(r, "not executable")
+                return False
+            if verbose:
+                print(r, "found and executable.")
+        return True
+
+
+    def run(self, verbose=False, runs=3):
+        for run in range(1, runs + 1):
+            print(str(run) + ". run")
+
+            n = len(self.nthreads)
+            for i, threads in enumerate(list(range(1, n + 1)) * 2):
+                print(i + 1, "of", n*2, "\r", end='')
+
+                # run cmd for each target
+                for tname, t in self.targets.items():
+                    result = {}
+
+                    os.environ["LD_PRELOAD"] = t[1]
+
+                    for bench in ["thrash", "scratch"]:
+
+                        target_cmd = cmd.format(bench, t[0], threads).split(" ")
+                        if verbose:
+                            print("\n" + tname, t, "\n", " ".join(target_cmd), "\n")
+
+                        p = subprocess.run(target_cmd,
+                                             env=os.environ,
+                                             stderr=subprocess.PIPE,
+                                             stdout=subprocess.PIPE,
+                                             universal_newlines=True)
+
+                        output = p.stdout
+
+                        if p.returncode != 0:
+                            print("\n" + " ".join(target_cmd), "exited with",
+                                    p.returncode, ".\n Aborting Benchmark.")
+                            print(tname, t)
+                            print(output)
+                            print(p.stdout)
+                            return False
+
+                        if "ERROR: ld.so" in output:
+                            print("\nPreloading of", t[1], "failed for", tname,
+                                    ".\n Aborting Benchmark.")
+                            print(output)
+                            return False
+
+                        # Handle perf output
+                        time = float(re.search("(\d*\.\d*)", str(output))[1])
+                        key = (tname, threads)
+                        if not key in self.results[bench]:
+                            self.results[bench][key] = [time]
+                        else:
+                            self.results[bench][key].append(time)
+
+            print()
+        return True
+
+    def summary(self):
+        # Speedup thrash
+        nthreads = self.results["args"]["nthreads"]
+        targets = self.results["targets"]
+
+        y_mapping = {v : i for i, v in enumerate(nthreads)}
+        for bench in ["thrash", "scratch"]:
+            for target in targets:
+                y_vals = [0] * len(nthreads)
+                single_threaded = np.mean(self.results[bench][(target, 1)])
+                y_vals[0] = single_threaded
+                for mid, measures in self.results[bench].items():
+                    print(measures)
+                    if mid[0] == target and mid[1] != 1:
+                        y_vals[y_mapping[mid[1]]] = single_threaded / np.mean(measures)
+                print(target, single_threaded, y_vals)
+                plt.plot(nthreads, y_vals, marker='.', linestyle='-', label=target)
+
+            plt.legend()
+            plt.xlabel("threads")
+            plt.ylabel("speedup")
+            plt.title(bench)
+            plt.savefig(self.name + "." + bench + ".png")
+            plt.clf()
+
+falsesharing= Benchmark_Falsesharing()
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