summaryrefslogtreecommitdiffstats
path: root/src/test/crush/crush.cc
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-21 11:54:28 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-21 11:54:28 +0000
commite6918187568dbd01842d8d1d2c808ce16a894239 (patch)
tree64f88b554b444a49f656b6c656111a145cbbaa28 /src/test/crush/crush.cc
parentInitial commit. (diff)
downloadceph-e6918187568dbd01842d8d1d2c808ce16a894239.tar.xz
ceph-e6918187568dbd01842d8d1d2c808ce16a894239.zip
Adding upstream version 18.2.2.upstream/18.2.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/crush/crush.cc')
-rw-r--r--src/test/crush/crush.cc660
1 files changed, 660 insertions, 0 deletions
diff --git a/src/test/crush/crush.cc b/src/test/crush/crush.cc
new file mode 100644
index 000000000..2d87958b3
--- /dev/null
+++ b/src/test/crush/crush.cc
@@ -0,0 +1,660 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2013 Inktank <info@inktank.com>
+ *
+ * LGPL-2.1 (see COPYING-LGPL2.1) or later
+ */
+
+#include <gtest/gtest.h>
+#include <iostream>
+#include <memory>
+#include <set>
+
+#include "common/ceph_argparse.h"
+#include "common/common_init.h"
+#include "include/stringify.h"
+
+#include "crush/CrushWrapper.h"
+#include "osd/osd_types.h"
+
+using namespace std;
+
+std::unique_ptr<CrushWrapper> build_indep_map(CephContext *cct, int num_rack,
+ int num_host, int num_osd)
+{
+ std::unique_ptr<CrushWrapper> c(new CrushWrapper);
+ c->create();
+
+ c->set_type_name(5, "root");
+ c->set_type_name(4, "row");
+ c->set_type_name(3, "rack");
+ c->set_type_name(2, "chasis");
+ c->set_type_name(1, "host");
+ c->set_type_name(0, "osd");
+
+ int rootno;
+ c->add_bucket(0, CRUSH_BUCKET_STRAW, CRUSH_HASH_RJENKINS1,
+ 5, 0, NULL, NULL, &rootno);
+ c->set_item_name(rootno, "default");
+
+ map<string,string> loc;
+ loc["root"] = "default";
+
+ int osd = 0;
+ for (int r=0; r<num_rack; ++r) {
+ loc["rack"] = string("rack-") + stringify(r);
+ for (int h=0; h<num_host; ++h) {
+ loc["host"] = string("host-") + stringify(r) + string("-") + stringify(h);
+ for (int o=0; o<num_osd; ++o, ++osd) {
+ c->insert_item(cct, osd, 1.0, string("osd.") + stringify(osd), loc);
+ }
+ }
+ }
+ int ret;
+ int ruleno = 0;
+ ret = c->add_rule(ruleno, 4, 123);
+ ceph_assert(ret == ruleno);
+ ret = c->set_rule_step(ruleno, 0, CRUSH_RULE_SET_CHOOSELEAF_TRIES, 10, 0);
+ ceph_assert(ret == 0);
+ ret = c->set_rule_step(ruleno, 1, CRUSH_RULE_TAKE, rootno, 0);
+ ceph_assert(ret == 0);
+ ret = c->set_rule_step(ruleno, 2, CRUSH_RULE_CHOOSELEAF_INDEP, CRUSH_CHOOSE_N, 1);
+ ceph_assert(ret == 0);
+ ret = c->set_rule_step(ruleno, 3, CRUSH_RULE_EMIT, 0, 0);
+ ceph_assert(ret == 0);
+ c->set_rule_name(ruleno, "data");
+
+ c->finalize();
+
+ if (false) {
+ Formatter *f = Formatter::create("json-pretty");
+ f->open_object_section("crush_map");
+ c->dump(f);
+ f->close_section();
+ f->flush(cout);
+ delete f;
+ }
+
+ return c;
+}
+
+int get_num_dups(const vector<int>& v)
+{
+ std::set<int> s;
+ int dups = 0;
+ for (auto n : v) {
+ if (s.count(n))
+ ++dups;
+ else if (n != CRUSH_ITEM_NONE)
+ s.insert(n);
+ }
+ return dups;
+}
+
+class CRUSHTest : public ::testing::Test
+{
+public:
+ void SetUp() final
+ {
+ CephInitParameters params(CEPH_ENTITY_TYPE_CLIENT);
+ cct = common_preinit(params, CODE_ENVIRONMENT_UTILITY,
+ CINIT_FLAG_NO_DEFAULT_CONFIG_FILE);
+ }
+ void TearDown() final
+ {
+ cct->put();
+ cct = nullptr;
+ }
+protected:
+ CephContext *cct = nullptr;
+};
+
+TEST_F(CRUSHTest, indep_toosmall) {
+ std::unique_ptr<CrushWrapper> c(build_indep_map(cct, 1, 3, 1));
+ vector<__u32> weight(c->get_max_devices(), 0x10000);
+ c->dump_tree(&cout, NULL);
+
+ for (int x = 0; x < 100; ++x) {
+ vector<int> out;
+ c->do_rule(0, x, out, 5, weight, 0);
+ cout << x << " -> " << out << std::endl;
+ int num_none = 0;
+ for (unsigned i=0; i<out.size(); ++i) {
+ if (out[i] == CRUSH_ITEM_NONE)
+ num_none++;
+ }
+ ASSERT_EQ(2, num_none);
+ ASSERT_EQ(0, get_num_dups(out));
+ }
+}
+
+TEST_F(CRUSHTest, indep_basic) {
+ std::unique_ptr<CrushWrapper> c(build_indep_map(cct, 3, 3, 3));
+ vector<__u32> weight(c->get_max_devices(), 0x10000);
+ c->dump_tree(&cout, NULL);
+
+ for (int x = 0; x < 100; ++x) {
+ vector<int> out;
+ c->do_rule(0, x, out, 5, weight, 0);
+ cout << x << " -> " << out << std::endl;
+ int num_none = 0;
+ for (unsigned i=0; i<out.size(); ++i) {
+ if (out[i] == CRUSH_ITEM_NONE)
+ num_none++;
+ }
+ ASSERT_EQ(0, num_none);
+ ASSERT_EQ(0, get_num_dups(out));
+ }
+}
+
+TEST_F(CRUSHTest, indep_out_alt) {
+ std::unique_ptr<CrushWrapper> c(build_indep_map(cct, 3, 3, 3));
+ vector<__u32> weight(c->get_max_devices(), 0x10000);
+
+ // mark a bunch of osds out
+ int num = 3*3*3;
+ for (int i=0; i<num / 2; ++i)
+ weight[i*2] = 0;
+ c->dump_tree(&cout, NULL);
+
+ // need more retries to get 9/9 hosts for x in 0..99
+ c->set_choose_total_tries(100);
+ for (int x = 0; x < 100; ++x) {
+ vector<int> out;
+ c->do_rule(0, x, out, 9, weight, 0);
+ cout << x << " -> " << out << std::endl;
+ int num_none = 0;
+ for (unsigned i=0; i<out.size(); ++i) {
+ if (out[i] == CRUSH_ITEM_NONE)
+ num_none++;
+ }
+ ASSERT_EQ(0, num_none);
+ ASSERT_EQ(0, get_num_dups(out));
+ }
+}
+
+TEST_F(CRUSHTest, indep_out_contig) {
+ std::unique_ptr<CrushWrapper> c(build_indep_map(cct, 3, 3, 3));
+ vector<__u32> weight(c->get_max_devices(), 0x10000);
+
+ // mark a bunch of osds out
+ int num = 3*3*3;
+ for (int i=0; i<num / 3; ++i)
+ weight[i] = 0;
+ c->dump_tree(&cout, NULL);
+
+ c->set_choose_total_tries(100);
+ for (int x = 0; x < 100; ++x) {
+ vector<int> out;
+ c->do_rule(0, x, out, 7, weight, 0);
+ cout << x << " -> " << out << std::endl;
+ int num_none = 0;
+ for (unsigned i=0; i<out.size(); ++i) {
+ if (out[i] == CRUSH_ITEM_NONE)
+ num_none++;
+ }
+ ASSERT_EQ(1, num_none);
+ ASSERT_EQ(0, get_num_dups(out));
+ }
+}
+
+
+TEST_F(CRUSHTest, indep_out_progressive) {
+ std::unique_ptr<CrushWrapper> c(build_indep_map(cct, 3, 3, 3));
+ c->set_choose_total_tries(100);
+ vector<__u32> tweight(c->get_max_devices(), 0x10000);
+ c->dump_tree(&cout, NULL);
+
+ int tchanged = 0;
+ for (int x = 1; x < 5; ++x) {
+ vector<__u32> weight(c->get_max_devices(), 0x10000);
+
+ std::map<int,unsigned> pos;
+ vector<int> prev;
+ for (unsigned i=0; i<weight.size(); ++i) {
+ vector<int> out;
+ c->do_rule(0, x, out, 7, weight, 0);
+ cout << "(" << i << "/" << weight.size() << " out) "
+ << x << " -> " << out << std::endl;
+ int num_none = 0;
+ for (unsigned k=0; k<out.size(); ++k) {
+ if (out[k] == CRUSH_ITEM_NONE)
+ num_none++;
+ }
+ ASSERT_EQ(0, get_num_dups(out));
+
+ // make sure nothing moved
+ int moved = 0;
+ int changed = 0;
+ for (unsigned j=0; j<out.size(); ++j) {
+ if (i && out[j] != prev[j]) {
+ ++changed;
+ ++tchanged;
+ }
+ if (out[j] == CRUSH_ITEM_NONE) {
+ continue;
+ }
+ if (i && pos.count(out[j])) {
+ // result shouldn't have moved position
+ if (j != pos[out[j]]) {
+ cout << " " << out[j] << " moved from " << pos[out[j]] << " to " << j << std::endl;
+ ++moved;
+ }
+ //ASSERT_EQ(j, pos[out[j]]);
+ }
+ }
+ if (moved || changed)
+ cout << " " << moved << " moved, " << changed << " changed" << std::endl;
+ ASSERT_LE(moved, 1);
+ ASSERT_LE(changed, 3);
+
+ // mark another osd out
+ weight[i] = 0;
+ prev = out;
+ pos.clear();
+ for (unsigned j=0; j<out.size(); ++j) {
+ if (out[j] != CRUSH_ITEM_NONE)
+ pos[out[j]] = j;
+ }
+ }
+ }
+ cout << tchanged << " total changed" << std::endl;
+
+}
+
+TEST_F(CRUSHTest, straw_zero) {
+ // zero weight items should have no effect on placement.
+
+ std::unique_ptr<CrushWrapper> c(new CrushWrapper);
+ const int ROOT_TYPE = 1;
+ c->set_type_name(ROOT_TYPE, "root");
+ const int OSD_TYPE = 0;
+ c->set_type_name(OSD_TYPE, "osd");
+
+ int n = 5;
+ int items[n], weights[n];
+ for (int i=0; i <n; ++i) {
+ items[i] = i;
+ weights[i] = 0x10000 * (n-i-1);
+ }
+
+ c->set_max_devices(n);
+
+ string root_name0("root0");
+ int root0;
+ EXPECT_EQ(0, c->add_bucket(0, CRUSH_BUCKET_STRAW, CRUSH_HASH_RJENKINS1,
+ ROOT_TYPE, n, items, weights, &root0));
+ EXPECT_EQ(0, c->set_item_name(root0, root_name0));
+
+ string name0("rule0");
+ int rule0 = c->add_simple_rule(name0, root_name0, "osd", "",
+ "firstn", pg_pool_t::TYPE_REPLICATED);
+ EXPECT_EQ(0, rule0);
+
+ string root_name1("root1");
+ int root1;
+ EXPECT_EQ(0, c->add_bucket(0, CRUSH_BUCKET_STRAW, CRUSH_HASH_RJENKINS1,
+ ROOT_TYPE, n-1, items, weights, &root1));
+ EXPECT_EQ(0, c->set_item_name(root1, root_name1));
+
+ string name1("rule1");
+ int rule1 = c->add_simple_rule(name1, root_name1, "osd", "",
+ "firstn", pg_pool_t::TYPE_REPLICATED);
+ EXPECT_EQ(1, rule1);
+
+ c->finalize();
+
+ vector<unsigned> reweight(n, 0x10000);
+ for (int i=0; i<10000; ++i) {
+ vector<int> out0, out1;
+ c->do_rule(rule0, i, out0, 1, reweight, 0);
+ ASSERT_EQ(1u, out0.size());
+ c->do_rule(rule1, i, out1, 1, reweight, 0);
+ ASSERT_EQ(1u, out1.size());
+ ASSERT_EQ(out0[0], out1[0]);
+ //cout << i << "\t" << out0 << "\t" << out1 << std::endl;
+ }
+}
+
+TEST_F(CRUSHTest, straw_same) {
+ // items with the same weight should map about the same as items
+ // with very similar weights.
+ //
+ // give the 0 vector a paired stair pattern, with dup weights. note
+ // that the original straw flaw does not appear when there are 2 of
+ // the initial weight, but it does when there is just 1.
+ //
+ // give the 1 vector a similar stair pattern, but make the same
+ // steps weights slightly different (no dups). this works.
+ //
+ // compare the result and verify that the resulting mapping is
+ // almost identical.
+
+ std::unique_ptr<CrushWrapper> c(new CrushWrapper);
+ const int ROOT_TYPE = 1;
+ c->set_type_name(ROOT_TYPE, "root");
+ const int OSD_TYPE = 0;
+ c->set_type_name(OSD_TYPE, "osd");
+
+ int n = 10;
+ int items[n], weights[n];
+ for (int i=0; i <n; ++i) {
+ items[i] = i;
+ weights[i] = 0x10000 * ((i+1)/2 + 1);
+ }
+
+ c->set_max_devices(n);
+
+ string root_name0("root0");
+ int root0;
+ EXPECT_EQ(0, c->add_bucket(0, CRUSH_BUCKET_STRAW, CRUSH_HASH_RJENKINS1,
+ ROOT_TYPE, n, items, weights, &root0));
+ EXPECT_EQ(0, c->set_item_name(root0, root_name0));
+
+ string name0("rule0");
+ int rule0 = c->add_simple_rule(name0, root_name0, "osd", "",
+ "firstn", pg_pool_t::TYPE_REPLICATED);
+ EXPECT_EQ(0, rule0);
+
+ for (int i=0; i <n; ++i) {
+ items[i] = i;
+ weights[i] = 0x10000 * ((i+1)/2 + 1) + (i%2)*100;
+ }
+
+ string root_name1("root1");
+ int root1;
+ EXPECT_EQ(0, c->add_bucket(0, CRUSH_BUCKET_STRAW, CRUSH_HASH_RJENKINS1,
+ ROOT_TYPE, n, items, weights, &root1));
+ EXPECT_EQ(0, c->set_item_name(root1, root_name1));
+
+ string name1("rule1");
+ int rule1 = c->add_simple_rule(name1, root_name1, "osd", "",
+ "firstn", pg_pool_t::TYPE_REPLICATED);
+ EXPECT_EQ(1, rule1);
+
+ if (0) {
+ crush_bucket_straw *sb0 = reinterpret_cast<crush_bucket_straw*>(c->get_crush_map()->buckets[-1-root0]);
+ crush_bucket_straw *sb1 = reinterpret_cast<crush_bucket_straw*>(c->get_crush_map()->buckets[-1-root1]);
+
+ for (int i=0; i<n; ++i) {
+ cout << i
+ << "\t" << sb0->item_weights[i]
+ << "\t" << sb1->item_weights[i]
+ << "\t"
+ << "\t" << sb0->straws[i]
+ << "\t" << sb1->straws[i]
+ << std::endl;
+ }
+ }
+
+ if (0) {
+ JSONFormatter jf(true);
+ jf.open_object_section("crush");
+ c->dump(&jf);
+ jf.close_section();
+ jf.flush(cout);
+ }
+
+ c->finalize();
+
+ vector<int> sum0(n, 0), sum1(n, 0);
+ vector<unsigned> reweight(n, 0x10000);
+ int different = 0;
+ int max = 100000;
+ for (int i=0; i<max; ++i) {
+ vector<int> out0, out1;
+ c->do_rule(rule0, i, out0, 1, reweight, 0);
+ ASSERT_EQ(1u, out0.size());
+ c->do_rule(rule1, i, out1, 1, reweight, 0);
+ ASSERT_EQ(1u, out1.size());
+ sum0[out0[0]]++;
+ sum1[out1[0]]++;
+ if (out0[0] != out1[0])
+ different++;
+ }
+ for (int i=0; i<n; ++i) {
+ cout << i
+ << "\t" << ((double)weights[i] / (double)weights[0])
+ << "\t" << sum0[i] << "\t" << ((double)sum0[i]/(double)sum0[0])
+ << "\t" << sum1[i] << "\t" << ((double)sum1[i]/(double)sum1[0])
+ << std::endl;
+ }
+ double ratio = ((double)different / (double)max);
+ cout << different << " of " << max << " = "
+ << ratio
+ << " different" << std::endl;
+ ASSERT_LT(ratio, .001);
+}
+
+double calc_straw2_stddev(int *weights, int n, bool verbose)
+{
+ std::unique_ptr<CrushWrapper> c(new CrushWrapper);
+ const int ROOT_TYPE = 2;
+ c->set_type_name(ROOT_TYPE, "root");
+ const int HOST_TYPE = 1;
+ c->set_type_name(HOST_TYPE, "host");
+ const int OSD_TYPE = 0;
+ c->set_type_name(OSD_TYPE, "osd");
+
+ int items[n];
+ for (int i=0; i <n; ++i) {
+ items[i] = i;
+ }
+
+ c->set_max_devices(n);
+
+ string root_name0("root0");
+ int root0;
+ crush_bucket *b0 = crush_make_bucket(c->get_crush_map(),
+ CRUSH_BUCKET_STRAW2, CRUSH_HASH_RJENKINS1,
+ ROOT_TYPE, n, items, weights);
+ crush_add_bucket(c->get_crush_map(), 0, b0, &root0);
+ c->set_item_name(root0, root_name0);
+
+ string name0("rule0");
+ int rule0 = c->add_simple_rule(name0, root_name0, "osd", "",
+ "firstn", pg_pool_t::TYPE_REPLICATED);
+
+ int sum[n];
+ double totalweight = 0;
+ vector<unsigned> reweight(n);
+ for (int i=0; i<n; ++i) {
+ sum[i] = 0;
+ reweight[i] = 0x10000;
+ totalweight += weights[i];
+ }
+ totalweight /= (double)0x10000;
+ double avgweight = totalweight / n;
+
+ c->finalize();
+
+ int total = 1000000;
+ for (int i=0; i<total; ++i) {
+ vector<int> out;
+ c->do_rule(rule0, i, out, 1, reweight, 0);
+ sum[out[0]]++;
+ }
+
+ double expected = (double)total / (double)n;
+ if (verbose)
+ cout << "expect\t\t\t" << expected << std::endl;
+ double stddev = 0;
+ double exptotal = 0;
+ if (verbose)
+ cout << "osd\tweight\tcount\tadjusted\n";
+ std::streamsize p = cout.precision();
+ cout << std::setprecision(4);
+ for (int i=0; i<n; ++i) {
+ double w = (double)weights[i] / (double)0x10000;
+ double adj = (double)sum[i] * avgweight / w;
+ stddev += (adj - expected) * (adj - expected);
+ exptotal += adj;
+ if (verbose)
+ cout << i
+ << "\t" << w
+ << "\t" << sum[i]
+ << "\t" << (int)adj
+ << std::endl;
+ }
+ cout << std::setprecision(p);
+ {
+ stddev = sqrt(stddev / (double)n);
+ if (verbose)
+ cout << "std dev " << stddev << std::endl;
+
+ double p = 1.0 / (double)n;
+ double estddev = sqrt(exptotal * p * (1.0 - p));
+ if (verbose)
+ cout << " vs " << estddev << "\t(expected)" << std::endl;
+ }
+ return stddev;
+}
+
+TEST_F(CRUSHTest, straw2_stddev)
+{
+ int n = 15;
+ int weights[n];
+ cout << "maxskew\tstddev\n";
+ for (double step = 1.0; step < 2; step += .25) {
+ int w = 0x10000;
+ for (int i = 0; i < n; ++i) {
+ weights[i] = w;
+ w *= step;
+ }
+ double stddev = calc_straw2_stddev(weights, n, true);
+ cout << ((double)weights[n-1]/(double)weights[0])
+ << "\t" << stddev << std::endl;
+ }
+}
+
+TEST_F(CRUSHTest, straw2_reweight) {
+ // when we adjust the weight of an item in a straw2 bucket,
+ // we should *only* see movement from or to that item, never
+ // between other items.
+ int weights[] = {
+ 0x10000,
+ 0x10000,
+ 0x20000,
+ 0x20000,
+ 0x30000,
+ 0x50000,
+ 0x8000,
+ 0x20000,
+ 0x10000,
+ 0x10000,
+ 0x20000,
+ 0x10000,
+ 0x10000,
+ 0x20000,
+ 0x300000,
+ 0x10000,
+ 0x20000
+ };
+ int n = 15;
+
+ std::unique_ptr<CrushWrapper> c(new CrushWrapper);
+ const int ROOT_TYPE = 2;
+ c->set_type_name(ROOT_TYPE, "root");
+ const int HOST_TYPE = 1;
+ c->set_type_name(HOST_TYPE, "host");
+ const int OSD_TYPE = 0;
+ c->set_type_name(OSD_TYPE, "osd");
+
+ int items[n];
+ for (int i=0; i <n; ++i) {
+ items[i] = i;
+ //weights[i] = 0x10000;
+ }
+
+ c->set_max_devices(n);
+
+ string root_name0("root0");
+ int root0;
+ crush_bucket *b0 = crush_make_bucket(c->get_crush_map(),
+ CRUSH_BUCKET_STRAW2, CRUSH_HASH_RJENKINS1,
+ ROOT_TYPE, n, items, weights);
+ EXPECT_EQ(0, crush_add_bucket(c->get_crush_map(), 0, b0, &root0));
+ EXPECT_EQ(0, c->set_item_name(root0, root_name0));
+
+ string name0("rule0");
+ int rule0 = c->add_simple_rule(name0, root_name0, "osd", "",
+ "firstn", pg_pool_t::TYPE_REPLICATED);
+ EXPECT_EQ(0, rule0);
+
+ int changed = 1;
+ weights[changed] = weights[changed] / 10 * (rand() % 10);
+
+ string root_name1("root1");
+ int root1;
+ crush_bucket *b1 = crush_make_bucket(c->get_crush_map(),
+ CRUSH_BUCKET_STRAW2, CRUSH_HASH_RJENKINS1,
+ ROOT_TYPE, n, items, weights);
+ EXPECT_EQ(0, crush_add_bucket(c->get_crush_map(), 0, b1, &root1));
+ EXPECT_EQ(0, c->set_item_name(root1, root_name1));
+
+ string name1("rule1");
+ int rule1 = c->add_simple_rule(name1, root_name1, "osd", "",
+ "firstn", pg_pool_t::TYPE_REPLICATED);
+ EXPECT_EQ(1, rule1);
+
+ int sum[n];
+ double totalweight = 0;
+ vector<unsigned> reweight(n);
+ for (int i=0; i<n; ++i) {
+ sum[i] = 0;
+ reweight[i] = 0x10000;
+ totalweight += weights[i];
+ }
+ totalweight /= (double)0x10000;
+ double avgweight = totalweight / n;
+
+ c->finalize();
+
+ int total = 1000000;
+ for (int i=0; i<total; ++i) {
+ vector<int> out0, out1;
+ c->do_rule(rule0, i, out0, 1, reweight, 0);
+ ASSERT_EQ(1u, out0.size());
+
+ c->do_rule(rule1, i, out1, 1, reweight, 0);
+ ASSERT_EQ(1u, out1.size());
+
+ sum[out1[0]]++;
+ //sum[rand()%n]++;
+
+ if (out1[0] == changed) {
+ ASSERT_EQ(changed, out0[0]);
+ } else if (out0[0] != changed) {
+ ASSERT_EQ(out0[0], out1[0]);
+ }
+ }
+
+ double expected = (double)total / (double)n;
+ cout << "expect\t\t\t" << expected << std::endl;
+ double stddev = 0;
+ cout << "osd\tweight\tcount\tadjusted\n";
+ std::streamsize p = cout.precision();
+ cout << std::setprecision(4);
+ for (int i=0; i<n; ++i) {
+ double w = (double)weights[i] / (double)0x10000;
+ double adj = (double)sum[i] * avgweight / w;
+ stddev += (adj - expected) * (adj - expected);
+ cout << i
+ << "\t" << w
+ << "\t" << sum[i]
+ << "\t" << (int)adj
+ << std::endl;
+ }
+ cout << std::setprecision(p);
+ {
+ stddev = sqrt(stddev / (double)n);
+ cout << "std dev " << stddev << std::endl;
+
+ double p = 1.0 / (double)n;
+ double estddev = sqrt((double)total * p * (1.0 - p));
+ cout << " vs " << estddev << std::endl;
+ }
+}