Remove my lame start sync and start recording before setup

Turns out mscan deals just fine with the benchmark setup

Remove my lame start sync and start recording before setup
8286b580 · Austin Clements · a036c823 · 8286b580 · 8286b580 · 8286b580
--- a/bin/dirbench.cc
+++ b/bin/dirbench.cc
@@ -22,10 +22,15 @@ static const bool pinit = true;
 enum { nfile = MTRACE ? 2 : 10 };
 enum { nlookup = MTRACE ? 2 : 100 };

+// XXX(austin) Totally lame.  Put this buffer in the BSS so we don't
+// have to COW fault the stack.
+static char pn[32]
+__attribute__((aligned(4096)));
+
 void
 bench(u32 tid, int nloop, const char* path)
 {
-  char pn[32];
+//  char pn[32];

  if (pinit)
    setaffinity(tid);
@@ -85,29 +90,17 @@ main(int ac, char** av)

  xmkdir(path);

-  int start[2];
-  if (pipe(start) < 0)
-    die("pipe");
+  mtenable_type(mtrace_record_ascope, "xv6-dirbench");

  u64 t0 = rdtsc();
  for(u32 i = 0; i < nthread; i++) {
    int pid = xfork();
    if (pid == 0) {
-      close(start[1]);
-      char token;
-      if (read(start[0], &token, 1) < 1)
-        die("read");
      bench(i, nloop, path);
    } else if (pid < 0)
      die("fork");
  }

-  mtenable_type(mtrace_record_ascope, "xv6-dirbench");
-
-  const char wakeup[256] = {};
-  if (write(start[1], wakeup, nthread) < nthread)
-    die("write");
-
  for (u32 i = 0; i < nthread; i++)
    xwait();
  u64 t1 = rdtsc();

--- a/bin/filebench.cc
+++ b/bin/filebench.cc
@@ -74,6 +74,8 @@ main(int ac, char **av)
  if (ac > 3)
    path = av[3];

+  mtenable_type(mtrace_record_ascope, "xv6-filebench");
+
  // Setup shared file
  unlink(path);
  int fd = xcreat(path);
@@ -86,31 +88,17 @@ main(int ac, char **av)
  }
  close(fd);

-  int start[2];
-  if (pipe(start) < 0)
-    die("pipe");
-
  //mtenable("xv6-filebench");
  u64 t0 = rdtsc();
  for (int i = 0; i < nthread; i++) {
    int pid = xfork();
    if (pid == 0) {
-      close(start[1]);
-      char token;
-      if (read(start[0], &token, 1) < 1)
-        die("read");
      bench(i, nloop, path);
    }
    else if (pid < 0)
      die("fork");
  }

-  mtenable_type(mtrace_record_ascope, "xv6-filebench");
-
-  const char wakeup[256] = {};
-  if (write(start[1], wakeup, nthread) < nthread)
-    die("write");
-
  for (int i = 0; i < nthread; i++)
    xwait();
  u64 t1 = rdtsc();

--- a/bin/mapbench.cc
+++ b/bin/mapbench.cc
@@ -37,8 +37,8 @@ thr(void *arg)

  pthread_barrier_wait(&bar);

-  if (tid == 0)
-    mtenable_type(mtrace_record_ascope, "xv6-asharing");
+  // if (tid == 0)
+  //   mtenable_type(mtrace_record_ascope, "xv6-asharing");

  pthread_barrier_wait(&bar2);

@@ -75,6 +75,8 @@ main(int ac, char **av)
  if (ac > 2)
    niter = atoi(av[2]);

+  mtenable_type(mtrace_record_ascope, "xv6-asharing");
+
  pthread_t* tid = (pthread_t*) malloc(sizeof(*tid)*nthread);

  pthread_barrier_init(&bar, 0, nthread);