1 files changed, 117 insertions, 0 deletions
diff --git a/src/tools/psim.cc b/src/tools/psim.cc
new file mode 100644
index 000000000..90e6fb958
--- /dev/null
+++ b/src/tools/psim.cc
@@ -0,0 +1,117 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "osd/OSDMap.h"
+#include "include/buffer.h"
+
+int main(int argc, char **argv)
+{
+  /*
+   * you need to create a suitable osdmap first.  e.g., for 40 osds, 
+   * $ ./osdmaptool --createsimple 40 --clobber .ceph_osdmap
+   */
+  bufferlist bl;
+  std::string error;
+  if (bl.read_file(".ceph_osdmap", &error)) {
+    cout << argv[0] << ": error reading .ceph_osdmap: " << error << std::endl;
+    return 1;
+  }
+  OSDMap osdmap;
+
+  try {
+    osdmap.decode(bl);
+  } catch (ceph::buffer::end_of_buffer &eob) {
+    cout << "Exception (end_of_buffer) in decode(), exit." << std::endl;
+    exit(1);
+  }
+
+  //osdmap.set_primary_affinity(0, 0x8000);
+  //osdmap.set_primary_affinity(3, 0);
+
+  int n = osdmap.get_max_osd();
+  int count[n];
+  int first_count[n];
+  int primary_count[n];
+  int size[4];
+
+  memset(count, 0, sizeof(count));
+  memset(first_count, 0, sizeof(first_count));
+  memset(primary_count, 0, sizeof(primary_count));
+  memset(size, 0, sizeof(size));
+
+  for (int i=0; i<n; i++) {
+    osdmap.set_state(i, osdmap.get_state(i) | CEPH_OSD_UP);
+    //if (i<12)
+      osdmap.set_weight(i, CEPH_OSD_IN);
+  }
+
+  //pg_pool_t *p = (pg_pool_t *)osdmap.get_pg_pool(0);
+  //p->type = pg_pool_t::TYPE_ERASURE;
+
+  for (int n = 0; n < 10; n++) {   // namespaces
+    char nspace[20];
+    snprintf(nspace, sizeof(nspace), "n%d", n);
+  for (int f = 0; f < 5000; f++) {  // files
+    for (int b = 0; b < 4; b++) {   // blocks
+      char foo[20];
+      snprintf(foo, sizeof(foo), "%d.%d", f, b);
+      object_t oid(foo);
+      ceph_object_layout l = osdmap.make_object_layout(oid, 0, nspace);
+      vector<int> osds;
+      pg_t pgid = pg_t(l.ol_pgid);
+      //pgid.u.ps = f * 4 + b;
+      int primary;
+      osdmap.pg_to_acting_osds(pgid, &osds, &primary);
+      size[osds.size()]++;
+#if 0
+      if (0) {
+	hash<object_t> H;
+	int x = H(oid);
+	x = ceph_stable_mod(x, 1023, 1023);
+	int s = crush_hash32(x) % 15;
+	//cout << "ceph_psim: x = " << x << " s = " << s << std::endl;
+	//osds[0] = s;
+      }
+#endif
+      //osds[0] = crush_hash32(f) % n;
+      //cout << "oid " << oid << " pgid " << pgid << " on " << osds << std::endl;
+      for (unsigned i=0; i<osds.size(); i++) {
+	//cout << " rep " << i << " on " << osds[i] << std::endl;
+	count[osds[i]]++;
+      }
+      if (osds.size())
+	first_count[osds[0]]++;
+      if (primary >= 0)
+	primary_count[primary]++;
+    }
+  }
+  }
+
+  uint64_t avg = 0;
+  for (int i=0; i<n; i++) {
+    cout << "osd." << i << "\t" << count[i]
+	 << "\t" << first_count[i]
+	 << "\t" << primary_count[i]
+	 << std::endl;
+    avg += count[i];
+  }
+  avg /= n;
+  double dev = 0;
+  for (int i=0; i<n; i++)
+    dev += (avg - count[i]) * (avg - count[i]);
+  dev /= n;
+  dev = sqrt(dev);
+
+  double pgavg = (double)osdmap.get_pg_pool(0)->get_pg_num() / (double)n;
+  double edev = sqrt(pgavg) * (double)avg / pgavg;
+  cout << " avg " << avg
+       << " stddev " << dev
+       << " (expected " << edev << ")"
+       << " (indep object placement would be " << sqrt(avg) << ")" << std::endl;
+
+  for (int i=0; i<4; i++) {
+    cout << "size" << i << "\t" << size[i] << std::endl;
+  }
+  
+  return 0;
+}