* In the download size indication, take binary patches into account.

Hopefully this doesn't slow things down too much.
This commit is contained in:
Eelco Dolstra 2010-11-17 17:32:25 +00:00
parent f69626ed3e
commit 3d38a49840
3 changed files with 168 additions and 145 deletions

View File

@ -31,6 +31,144 @@ for my $manifest (glob "$manifestDir/*.nixmanifest") {
} }
sub isValidPath {
my $p = shift;
return system("$binDir/nix-store --check-validity '$p' 2> /dev/null") == 0;
}
sub parseHash {
my $hash = shift;
if ($hash =~ /^(.+):(.+)$/) {
return ($1, $2);
} else {
return ("md5", $hash);
}
}
# Compute the most efficient sequence of downloads to produce the
# given path.
sub computeSmallestDownload {
my $targetPath = shift;
# Build a graph of all store paths that might contribute to the
# construction of $targetPath, and the special node "start". The
# edges are either patch operations, or downloads of full NAR
# files. The latter edges only occur between "start" and a store
# path.
my %graph;
$graph{"start"} = {d => 0, pred => undef, edges => []};
my @queue = ();
my $queueFront = 0;
my %done;
sub addNode {
my $graph = shift;
my $u = shift;
$$graph{$u} = {d => 999999999999, pred => undef, edges => []}
unless defined $$graph{$u};
}
sub addEdge {
my $graph = shift;
my $u = shift;
my $v = shift;
my $w = shift;
my $type = shift;
my $info = shift;
addNode $graph, $u;
push @{$$graph{$u}->{edges}},
{weight => $w, start => $u, end => $v, type => $type, info => $info};
my $n = scalar @{$$graph{$u}->{edges}};
}
push @queue, $targetPath;
while ($queueFront < scalar @queue) {
my $u = $queue[$queueFront++];
return if defined $done{$u};
$done{$u} = 1;
addNode \%graph, $u;
# If the path already exists, it has distance 0 from the
# "start" node.
if (isValidPath($u)) {
addEdge \%graph, "start", $u, 0, "present", undef;
}
else {
# Add patch edges.
my $patchList = $patches{$u};
foreach my $patch (@{$patchList}) {
if (isValidPath($patch->{basePath})) {
# !!! this should be cached
my ($baseHashAlgo, $baseHash) = parseHash $patch->{baseHash};
my $format = "--base32";
$format = "" if $baseHashAlgo eq "md5";
my $hash = `$binDir/nix-hash --type '$baseHashAlgo' $format "$patch->{basePath}"`;
chomp $hash;
next if $hash ne $baseHash;
}
push @queue, $patch->{basePath};
addEdge \%graph, $patch->{basePath}, $u, $patch->{size}, "patch", $patch;
}
# Add NAR file edges to the start node.
my $narFileList = $narFiles{$u};
foreach my $narFile (@{$narFileList}) {
# !!! how to handle files whose size is not known in advance?
# For now, assume some arbitrary size (1 MB).
addEdge \%graph, "start", $u, ($narFile->{size} || 1000000), "narfile", $narFile;
}
}
}
# Run Dijkstra's shortest path algorithm to determine the shortest
# sequence of download and/or patch actions that will produce
# $targetPath.
my @todo = keys %graph;
while (scalar @todo > 0) {
# Remove the closest element from the todo list.
# !!! inefficient, use a priority queue
@todo = sort { -($graph{$a}->{d} <=> $graph{$b}->{d}) } @todo;
my $u = pop @todo;
my $u_ = $graph{$u};
foreach my $edge (@{$u_->{edges}}) {
my $v_ = $graph{$edge->{end}};
if ($v_->{d} > $u_->{d} + $edge->{weight}) {
$v_->{d} = $u_->{d} + $edge->{weight};
# Store the edge; to edge->start is actually the
# predecessor.
$v_->{pred} = $edge;
}
}
}
# Retrieve the shortest path from "start" to $targetPath.
my @path = ();
my $cur = $targetPath;
return () unless defined $graph{$targetPath}->{pred};
while ($cur ne "start") {
push @path, $graph{$cur}->{pred};
$cur = $graph{$cur}->{pred}->{start};
}
return @path;
}
# Parse the arguments. # Parse the arguments.
if ($ARGV[0] eq "--query") { if ($ARGV[0] eq "--query") {
@ -46,6 +184,7 @@ if ($ARGV[0] eq "--query") {
elsif ($cmd eq "info") { elsif ($cmd eq "info") {
my $storePath = <STDIN>; chomp $storePath; my $storePath = <STDIN>; chomp $storePath;
my $info; my $info;
if (defined $narFiles{$storePath}) { if (defined $narFiles{$storePath}) {
$info = @{$narFiles{$storePath}}[0]; $info = @{$narFiles{$storePath}}[0];
@ -57,13 +196,30 @@ if ($ARGV[0] eq "--query") {
print "0\n"; print "0\n";
next; # not an error next; # not an error
} }
print "1\n"; print "1\n";
print "$info->{deriver}\n"; print "$info->{deriver}\n";
my @references = split " ", $info->{references}; my @references = split " ", $info->{references};
print scalar @references, "\n"; print scalar @references, "\n";
print "$_\n" foreach @references; print "$_\n" foreach @references;
my $size = $info->{size} || 0;
print "$size\n"; my @path = computeSmallestDownload $storePath;
my $downloadSize = 0;
while (scalar @path > 0) {
my $edge = pop @path;
my $u = $edge->{start};
my $v = $edge->{end};
if ($edge->{type} eq "patch") {
$downloadSize += $edge->{info}->{size};
}
elsif ($edge->{type} eq "narfile") {
$downloadSize += $edge->{info}->{size};
}
}
print "$downloadSize\n";
my $narSize = $info->{narSize} || 0; my $narSize = $info->{narSize} || 0;
print "$narSize\n"; print "$narSize\n";
} }
@ -112,148 +268,9 @@ foreach my $localPath (@{$localPathList}) {
} }
# Build a graph of all store paths that might contribute to the # Compute the shortest path.
# construction of $targetPath, and the special node "start". The my @path = computeSmallestDownload $targetPath;
# edges are either patch operations, or downloads of full NAR files. die "don't know how to produce $targetPath\n" if scalar @path == 0;
# The latter edges only occur between "start" and a store path.
my %graph;
$graph{"start"} = {d => 0, pred => undef, edges => []};
my @queue = ();
my $queueFront = 0;
my %done;
sub addToQueue {
my $v = shift;
return if defined $done{$v};
$done{$v} = 1;
push @queue, $v;
}
sub addNode {
my $u = shift;
$graph{$u} = {d => 999999999999, pred => undef, edges => []}
unless defined $graph{$u};
}
sub addEdge {
my $u = shift;
my $v = shift;
my $w = shift;
my $type = shift;
my $info = shift;
addNode $u;
push @{$graph{$u}->{edges}},
{weight => $w, start => $u, end => $v, type => $type, info => $info};
my $n = scalar @{$graph{$u}->{edges}};
}
addToQueue $targetPath;
sub isValidPath {
my $p = shift;
return system("$binDir/nix-store --check-validity '$p' 2> /dev/null") == 0;
}
sub parseHash {
my $hash = shift;
if ($hash =~ /^(.+):(.+)$/) {
return ($1, $2);
} else {
return ("md5", $hash);
}
}
while ($queueFront < scalar @queue) {
my $u = $queue[$queueFront++];
# print "$u\n";
addNode $u;
# If the path already exists, it has distance 0 from the "start"
# node.
if (isValidPath($u)) {
addEdge "start", $u, 0, "present", undef;
}
else {
# Add patch edges.
my $patchList = $patches{$u};
foreach my $patch (@{$patchList}) {
if (isValidPath($patch->{basePath})) {
# !!! this should be cached
my ($baseHashAlgo, $baseHash) = parseHash $patch->{baseHash};
my $format = "--base32";
$format = "" if $baseHashAlgo eq "md5";
my $hash = `$binDir/nix-hash --type '$baseHashAlgo' $format "$patch->{basePath}"`;
chomp $hash;
if ($hash ne $baseHash) {
print LOGFILE "$$ rejecting $patch->{basePath}\n";
next;
}
}
addToQueue $patch->{basePath};
addEdge $patch->{basePath}, $u, $patch->{size}, "patch", $patch;
}
# Add NAR file edges to the start node.
my $narFileList = $narFiles{$u};
foreach my $narFile (@{$narFileList}) {
# !!! how to handle files whose size is not known in advance?
# For now, assume some arbitrary size (1 MB).
addEdge "start", $u, ($narFile->{size} || 1000000), "narfile", $narFile;
if ($u eq $targetPath) {
my $size = $narFile->{size} || -1;
print LOGFILE "$$ full-download-would-be $size\n";
}
}
}
}
# Run Dijkstra's shortest path algorithm to determine the shortest
# sequence of download and/or patch actions that will produce
# $targetPath.
sub byDistance { # sort by distance, reversed
return -($graph{$a}->{d} <=> $graph{$b}->{d});
}
my @todo = keys %graph;
while (scalar @todo > 0) {
# Remove the closest element from the todo list.
@todo = sort byDistance @todo;
my $u = pop @todo;
my $u_ = $graph{$u};
foreach my $edge (@{$u_->{edges}}) {
my $v_ = $graph{$edge->{end}};
if ($v_->{d} > $u_->{d} + $edge->{weight}) {
$v_->{d} = $u_->{d} + $edge->{weight};
# Store the edge; to edge->start is actually the
# predecessor.
$v_->{pred} = $edge;
}
}
}
# Retrieve the shortest path from "start" to $targetPath.
my @path = ();
my $cur = $targetPath;
die "don't know how to produce $targetPath\n"
unless defined $graph{$targetPath}->{pred};
while ($cur ne "start") {
push @path, $graph{$cur}->{pred};
$cur = $graph{$cur}->{pred}->{start};
}
# Traverse the shortest path, perform the actions described by the # Traverse the shortest path, perform the actions described by the

View File

@ -9,7 +9,7 @@ mkDerivation {
mkdir $out mkdir $out
seq 1 1000000 > $out/foo seq 1 1000000 > $out/foo
${if version == 2 then '' ${if version == 2 then ''
echo bla >> $out/foo seq 1000000 1010000 >> $out/foo
'' else ""} '' else ""}
''; '';
} }

View File

@ -1,5 +1,7 @@
source common.sh source common.sh
clearManifests
mkdir -p $TEST_ROOT/cache2 $TEST_ROOT/patches mkdir -p $TEST_ROOT/cache2 $TEST_ROOT/patches
RESULT=$TEST_ROOT/result RESULT=$TEST_ROOT/result
@ -29,5 +31,9 @@ $NIX_BIN_DIR/nix-pull file://$TEST_ROOT/manifest2
# To make sure that we're using the patch, delete the full NARs. # To make sure that we're using the patch, delete the full NARs.
rm -f $TEST_ROOT/cache2/* rm -f $TEST_ROOT/cache2/*
# Make sure that the download size prediction uses the patch rather
# than the full download.
$nixbuild -o $RESULT binary-patching.nix --arg version 2 --dry-run 2>&1 | grep -q "0.01 MiB"
# Now rebuild it. This should use the patch generated above. # Now rebuild it. This should use the patch generated above.
$nixbuild -o $RESULT binary-patching.nix --arg version 2 $nixbuild -o $RESULT binary-patching.nix --arg version 2