Import utilit z meho soukromeho repozitare

README

-Brum :)
+Materialy k predmetu Algoritmy a jejich implementace
+
+Komentare vitany na <aim@ucw.cz>.

access/Makefile

+CC=gcc
+LD=gcc
+CFLAGS=-O2 -Wall -W -Wno-parentheses -Wstrict-prototypes -Wmissing-prototypes -Wundef -Wredundant-decls -std=gnu99
+
+all: access
+
+access: access.c
+access: CFLAGS+=$(F)
+F=-DSIZE=16 -DMS=1000
+
+clean:
+	rm -f `find . -name "*~" -or -name "*.[oa]" -or -name "\#*\#" -or -name TAGS -or -name core -or -name .depend -or -name .#*`
+	rm -f access a-* plot.gp

access/README

+Jak pouzivat merici utilitku:
+
+(1) make clean -- smaze pracovni soubory z pripadnych predchozich behu.
+
+(2) make -- tim vyzkousite, ze testovaci program jde zkompilovat.
+
+(3) ./graph.pl -- ridici skript, ktery testovaci program kompiluje
+s ruznymi parametry, spousti ho a loguje vysledky. Take vytvari soubor
+plot.gp pro GnuPlot. Na zacatku skriptu jsou nastavitelne parametry.
+
+(4) gnuplot plot.gp -- vyrobi a-*.png s grafy.

access/access.c

+/*
+ *	A simple memory access speed test
+ *
+ *	Written by Martin Mares <mj@ucw.cz> and put into public domain.
+ *
+ *	Compile-time switches:
+ *	  SIZE=xxx	Size of a single item in bytes
+ *	  RANDOMIZE	Define for random access, undef for sequential
+ *	  MODIFY	Define for read-write accesses, undef for read-only
+ *	  MS		Measurement period in ms
+ *	  ARRAY		Access items as array (default: linked list)
+ *	  HUGE		Allocate huge pages (hugetlbfs required)
+ *
+ *	Output is in nanoseconds per access.
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/time.h>
+#include <time.h>
+
+struct item {
+  struct item *next;
+  uint32_t pad[(SIZE-sizeof(struct item *)) / 4];
+};
+
+static struct item *items;
+static unsigned block_size, n;
+
+#define TICKS_PER_SEC 1000000
+static int64_t get_timer(void)
+{
+  struct timeval t;
+  gettimeofday(&t, NULL);
+  return 1000000*t.tv_sec + t.tv_usec;
+}
+
+#ifdef HUGE
+
+static void alloc_mem(void)
+{
+#define HUGE_PATH "huge/access"
+#define HUGE_PAGE (2*1048576)
+  void *pp;
+  unlink(HUGE_PATH);
+  int fd = open(HUGE_PATH, O_RDWR | O_CREAT, 0644);
+  if (fd < 0)
+    {
+      fprintf(stderr, "Cannot open hugetlbfs at %s: %m\n", HUGE_PATH);
+      exit(1);
+    }
+  if ((pp = mmap(NULL, ((block_size+HUGE_PAGE-1)/HUGE_PAGE)*HUGE_PAGE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED)
+    {
+      fprintf(stderr, "Cannot mmap hugetlbfs: %m\n");
+      exit(1);
+    }
+  items = pp;
+}
+
+#else
+
+static void alloc_mem(void)
+{
+  void *pp;
+  if (posix_memalign(&pp, 4096, block_size) < 0)
+    {
+      fprintf(stderr, "Cannot allocate memory: %m\n");
+      exit(1);
+    }
+  items = pp;
+}
+
+#endif
+
+static inline void eat(uint32_t x)
+{
+  // Discard a value, but do not allow optimizing it out
+  asm volatile ("" : : "r" (x));
+}
+
+static inline void process_item(struct item *x)
+{
+#ifdef MODIFY
+  x->pad[0]++;
+#else
+  eat(x->pad[0]);
+#endif
+}
+
+#ifdef ARRAY
+
+static void fill(void)
+{
+  memset(items, 0, block_size);
+}
+
+static void loop(void)
+{
+#ifdef RANDOMIZE
+  if (n & (n-1))
+    {
+      fprintf(stderr, "Block size must be a power of two!\n");
+      exit(1);
+    }
+  unsigned i=0;
+  do
+    {
+      process_item(&items[i]);
+      i = (i+259309) & (n-1);
+    }
+  while (i);
+#else
+  struct item *stop = items + n;
+  for (struct item *a = items; a < stop; a++)
+    process_item(a);
+#endif
+}
+
+#else
+
+static void fill(void)
+{
+  memset(items, 0, block_size);
+#ifdef RANDOMIZE
+  for (unsigned i=0; i<n; i++)
+    {
+      unsigned j=(i+259309) % n;
+      if (j)
+	items[i].next = &items[j];
+    }
+#else
+  for (unsigned i=0; i<n-1; i++)
+    items[i].next = &items[i+1];
+#endif
+}
+
+static void loop(void)
+{
+  for (struct item *a = items; a; a=a->next)
+    process_item(a);
+}
+
+#endif
+
+int main(int argc, char **argv)
+{
+  if (argc != 2)
+    {
+      fprintf(stderr, "Usage: access <size-in-KB>\n");
+      return 1;
+    }
+  block_size = atoi(argv[1]) * 1024;
+  n = block_size / SIZE;
+
+  alloc_mem();
+  fill();
+
+  unsigned attempts = 1;
+  for (;;)
+    {
+      int64_t t0 = get_timer();
+
+      for (unsigned i=0; i<attempts; i++)
+	loop();
+
+      int64_t t1 = get_timer();
+      int64_t t = t1-t0;
+      if (t >= TICKS_PER_SEC/1000*MS)
+	{
+	  printf("%.3f %f\n", (double)t/attempts/n/TICKS_PER_SEC*1e9, (double)(2*attempts-1)*n);
+	  break;
+	}
+      attempts *= 2;
+    }
+
+  return 0;
+}

access/graph.pl

+#!/usr/bin/perl
+
+my $min_mem = 8;	# Minimum memory block size (KB)
+my $max_mem = 65536;	# Maximum memory block size (KB), must fit in physical memory
+my @item_sizes = (16,64,128,1024,4096);	# Sizes of items
+my @randomized = (0,1);	# Try randomized accesses?
+my @modify = (0,1);	# Try read-write accesses?
+my $measure_ms = 1000;	# Duration of measurement in ms
+my $array = 0;		# Items are accessed as an array instead of a list
+my $huge = 0;		# Use huge pages (hugetlbfs required)
+
+# If you want to include profiling information (cache misses etc.) in detailed
+# graphs, you can ask the measurement utility to call oprofile. Please note that
+# this requires root privileges and that you need to adjust the profiling events
+# below to match your CPU (see `opcontrol --list-events'). Also, it might be
+# necessary to increase $measure_ms in order to gather enough samples.
+my %oprofile = (
+## AMD K8 Family 10 (4 counters)
+#	"DATA_CACHE_MISSES" => 10000,
+#	"L2_CACHE_MISS" => 10000,
+#	"DRAM_ACCESSES" => "10000:0xff",
+#	"L1_DTLB_AND_L2_DTLB_MISS" => 10000,
+##	"L1_DTLB_MISS_AND_L2_DTLB_HIT" => 10000,
+## Intel Core (2 counters)
+#	"DTLB_MISSES" => 10000,
+#	"BUS_TRAN_MEM" => 10000,		# Memory transactions on the bus
+## Intel i7 (4 counters)
+#	"DTLB_MISSES" => 10000,
+#	"MEM_UNCORE_RETIRED" => "10000:0x30",	# Memory transactions (local DRAM)
+#	"L2_RQSTS" => "10000:0xaa",		# L2 misses
+#	"L1D" => "10000",			# Lines brought to L1
+##	"LLC_MISSES" => 10000,			# Last-Level Cache (L3) misses
+##	"OFFCORE_REQUESTS" => "10000:0x08",	# Off-core read requests
+);
+my @oprofile_events = sort keys %oprofile;
+
+# Use --graph to disable all calculations and just re-use the log files
+my $graph_only = 0;
+if (@ARGV && $ARGV[0] eq "--graph") {
+	$graph_only = 1;
+	shift @ARGV;
+}
+
+# Use ./graph.pl <directory> to store results in a separate directory
+if (defined $ARGV[0]) {
+	my $dir = $ARGV[0];
+	-d $dir or mkdir $dir or die "Cannot create $dir";
+	chdir $dir or die;
+	for my $f ("access.c", "Makefile", "parse_op") {
+		-f $f or symlink "../$f", $f or die;
+	}
+}
+
+### Get machine name and the description of caches ###
+
+my $machine = `hostname`;
+chomp $machine;
+$machine .= " Array" if $array;
+$machine .= " HugePages" if $huge;
+$machine = "($machine)";
+
+our $c;
+my @caches = ();
+for $c (</sys/devices/system/cpu/cpu0/cache/index*>) {
+	sub rd($) {
+		my ($f) = @_;
+		open F, "$c/$f" or return "";
+		my $x = <F>;
+		close F;
+		chomp $x;
+		return $x;
+	}
+
+	my $l = rd("level");
+	my $w = rd("ways_of_associativity");
+	my $s = rd("size");
+	my $t = rd("type");
+	my $L = rd("coherency_line_size");
+	$t =~ s/(.).*/$1/;
+	$t =~ s/U//;
+	$t eq "I" and next;
+	push @caches, "L$l$t $s/$L $w-way";
+}
+$machine .= " [" . join(", ", @caches) . "]";
+
+### Interface to oprofile ###
+
+sub oprof(@) {
+	system "opcontrol", @_ and die "opcontrol " . join(" ", @_) . " failed ($?)";
+}
+
+sub profile_setup() {
+	%oprofile or return;
+	oprof("--shutdown");
+	oprof("--setup", map { "--event=" . $_ . ":" . $oprofile{$_} } sort keys %oprofile);
+	oprof("--start");
+}
+
+sub profile_shutdown() {
+	%oprofile or return;
+	oprof("--shutdown");
+	oprof("--reset");
+}
+
+sub profile_start() {
+	%oprofile or return;
+	oprof("--reset");
+}
+
+sub profile_stop() {
+	%oprofile or return ();
+	oprof("--dump");
+	if (system "opreport", "./access", "--xml", "--output-file=op.xml") {
+		print STDERR "opreport failed: $?, assuming that no samples were gathered\n";
+		return ();
+	}
+	open P, "./parse_op op.xml |" or die "parse_op failed";
+	my %evt = ();
+	while (<P>) {
+		chomp;
+		my ($k, $v) = split /\s+/;
+		$evt{$k} = $v;
+	}
+	close P;
+	my @prof = ();
+	for my $e (@oprofile_events) {
+		my $mul = $oprofile{$e};
+		$mul =~ s/:.*//;
+		push @prof, ($evt{$e} || 0) * 1. * $mul;
+	}
+	return @prof;
+}
+
+### Measure and create logs ###
+
+if (!$graph_only) {
+	profile_setup();
+	for my $r (@randomized) {
+		for my $m (@modify) {
+			for my $s (@item_sizes) {
+				my $f = "a-$r-$m-$s.log";
+				next if -f $f;
+				my @o = ( "-DSIZE=$s", "-DMS=$measure_ms" );
+				push @o, "-DRANDOMIZE" if $r;
+				push @o, "-DMODIFY" if $m;
+				push @o, "-DARRAY" if $array;
+				push @o, "-DHUGE" if $huge;
+				my $o = join(" ", @o);
+				`rm -f access`; die if $?;
+				`make access F="$o"`; die if $?;
+				open D, ">$f" or die;
+				for (my $mem=$min_mem; $mem<=$max_mem; $mem*=2) {
+					profile_start();
+					my $out = `./access $mem`; die if $?;
+					my ($t, $attempts) = split /\s+/, $out;
+					my @prof = profile_stop();
+					@prof = map { $_ / $attempts } @prof;
+					chomp $t;
+					print "$mem ($o): ", join(" ", $t,
+						map { $oprofile_events[$_] . ":" . sprintf("%.3f", $prof[$_]) } 0..$#prof),
+						"\n";
+					print D join("\t", $mem, $t, @prof), "\n";
+				}
+				close D;
+			}
+		}
+	}
+	profile_shutdown();
+}
+
+### The plots ###
+
+# Generic header
+open GP, ">plot.gp" or die;
+print GP <<EOF ;
+set terminal png large size 1024,768
+set logscale x 2
+set key left
+set xlabel "data set size [KB]"
+set ylabel "time per access [ns]"
+set grid
+set yrange [1:120]	# Change if necessary
+
+EOF
+
+# For each access type, show different sizes
+for my $r (@randomized) {
+	for my $m (@modify) {
+		my @plots = ();
+		for my $s (@item_sizes) {
+			push @plots, "'a-$r-$m-$s.log' title '${s}B items' with linespoints";
+		}
+		print GP "set output 'a-$r-$m.png'\n";
+		my $title = ($r ? "Random" : "Sequential") . " " . ($m ? "Read-Write" : "Read-Only") . " Accesses $machine";
+		print GP "set title '$title'\n";
+		print GP "plot ", join(", ", @plots), "\n\n";
+	}
+}
+
+# For each item size, show all access types
+for my $s (@item_sizes) {
+	print GP "set output 'a-size-$s.png'\n";
+	print GP "set title 'Item size $s $machine'\n";
+	my @a = ();
+	for my $r (@randomized) {
+		for my $m (@modify) {
+			my $t = ($r ? "Random" : "Sequential") . " " . ($m ? "R+W" : "R");
+			push @a, "'a-$r-$m-$s.log' title '$t' with linespoints";
+		}
+	}
+	print GP "plot ", join(", ", @a), "\n\n";
+}
+
+# For each item size and access type, show full profiling information
+if (%oprofile) {
+	for my $s (@item_sizes) {
+		for my $r (@randomized) {
+			for my $m (@modify) {
+				print GP "set output 'a-prof-$s-$r-$m.png'\n";
+				my $title = "Profile for " . ($r ? "Random" : "Sequential") . " " . ($m ? "Read-Write" : "Read-Only") . " $s bytes $machine";
+				print GP "set title '$title'\n";
+				print GP "set y2label 'number of events'\n";
+				print GP "set y2tics\n";
+				print GP "set y2range [0:3]\n";
+				my @a = ();
+				push @a, "'a-$r-$m-$s.log' title 'Time' with linespoints";
+				for my $i (0..$#oprofile_events) {
+					push @a, "'' using 1:" . ($i+3) . " axes x1y2 title '" . $oprofile_events[$i] . "' with linespoints";
+				}
+				print GP "plot ", join(", ", @a), "\n\n";
+			}
+		}
+	}
+}
+
+close GP;