1 files changed, 76 insertions, 0 deletions
diff --git a/src/falsesharing.py b/src/falsesharing.py
new file mode 100644
index 0000000..1e0ef18
--- /dev/null
+++ b/src/falsesharing.py
@@ -0,0 +1,76 @@
+import matplotlib.pyplot as plt
+import multiprocessing
+import numpy as np
+import os
+import re
+
+from src.benchmark import Benchmark
+
+time_re = re.compile("^Time elapsed = (?P<time>\d*\.\d*) seconds.$")
+
+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 thrashing."""
+
+        self.cmd = "build/cache-{bench}{binary_suffix} {threads} 100 8 1000000"
+
+        self.args = {
+                        "bench" : ["thrash", "scratch"],
+                        "threads" : range(1, multiprocessing.cpu_count() * 2 + 1)
+                    }
+
+        self.requirements = ["build/cache-thrash", "build/cache-scratch"]
+        super().__init__()
+
+    def process_output(self, result, stdout, stderr, target, perm, verbose):
+        result["time"] = time_re.match(stdout).group("time")
+
+    def summary(self, sumdir=None):
+        # Speedup thrash
+        args = self.results["args"]
+        nthreads = args["threads"]
+        targets = self.results["targets"]
+
+        for bench in self.results["args"]["bench"]:
+            for target in targets:
+                y_vals = []
+
+                single_threaded_perm = self.Perm(bench=bench, threads=1)
+                single_threaded = np.mean([float(m["time"])
+                                                    for m in self.results[target][single_threaded_perm]])
+
+                for perm in self.iterate_args_fixed({"bench" : bench}, args=args):
+
+                    d = [float(m["time"]) for m in self.results[target][perm]]
+
+                    y_vals.append(single_threaded / np.mean(d))
+
+                plt.plot(nthreads, y_vals, marker='.', linestyle='-', label=target,
+                            color=targets[target]["color"])
+
+            plt.legend()
+            plt.xlabel("threads")
+            plt.ylabel("speedup")
+            plt.title(bench + " speedup" )
+            plt.savefig(os.path.join(sumdir, self.name + "." + bench + ".png"))
+            plt.clf()
+
+        self.plot_fixed_arg("({L1-dcache-load-misses}/{L1-dcache-loads})*100",
+                    ylabel="'l1 cache misses in %'",
+                    title = "'cache misses: ' + arg + ' ' + str(arg_value)",
+                    filepostfix = "l1-misses",
+                    sumdir=sumdir,
+                    fixed=["bench"])
+
+        self.plot_fixed_arg("({LLC-load-misses}/{LLC-loads})*100",
+                    ylabel="'l1 cache misses in %'",
+                    title = "'LLC misses: ' + arg + ' ' + str(arg_value)",
+                    filepostfix = "llc-misses",
+                    sumdir=sumdir,
+                    fixed=["bench"])
+
+falsesharing = Benchmark_Falsesharing()