First attempt at some performance tracking tools. Includes a script vg_perf
(use "make perf" to run) that executes test programs and times their
slowdowns under various tools. It works a lot like the vg_regtest script.
It's a bit rough around the edges -- eg. you can't currently directly
compare two different versions of Valgrind, which would be useful -- but it
is a good start.
There are currently two test programs in perf/. More will be added as time
goes on. This stuff will be built on so that performance changes can be
tracked over time.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@5323 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/perf/sarp.c b/perf/sarp.c
new file mode 100644
index 0000000..04518d6
--- /dev/null
+++ b/perf/sarp.c
@@ -0,0 +1,46 @@
+// This artificial program allocates and deallocates a lot of large objects
+// on the stack. It is a stress test for Memcheck's set_address_range_perms
+// (sarp) function. Pretty much all Valgrind versions up to 3.1.X do very
+// badly on it, ie. a slowdown of at least 100x.
+//
+// It is representative of tsim_arch, the simulator for the University of
+// Texas's TRIPS processor, whose performance under Valgrind is dominated by
+// the handling of one frequently-called function that allocates 8348 bytes
+// on the stack.
+
+#include <assert.h>
+#include <time.h>
+
+#define REPS 1000*1000
+
+int f(int i)
+{
+ // This nonsense is just to ensure that the compiler does not optimise
+ // away the stack allocation.
+ char big_array[8348];
+ big_array[0] = 12;
+ big_array[2333] = 34;
+ big_array[5678] = 56;
+ big_array[8347] = 78;
+ assert( 8000 == (&big_array[8100] - &big_array[100]) );
+ return big_array[i];
+}
+
+int main(void)
+{
+ int i, sum = 0;
+
+ struct timespec req;
+ req.tv_sec = 0;
+ req.tv_nsec = 100*1000*1000; // 0.1s
+
+ // Pause for a bit so that the native run-time is not 0.00, which leads
+ // to ridiculous slow-down figures.
+ nanosleep(&req, NULL);
+
+ for (i = 0; i < REPS; i++) {
+ sum += f(i & 0xff);
+ }
+ return sum % 256;
+}
+