[Routing] Optimised dumped router matcher, prevent unneeded function calls. #21755

frankdejonge · 2017-02-24T22:43:17Z

Q	A
Branch?	master
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Fixed tickets	none
License	MIT
Doc PR	does not apply

The application I'm working on is fairly large. Because we had a routing issue (not caused by the framework) I looked through the dumped routing code. I spotted some easy wins. These changes brought down the time for the match method to run from ~ 7.5ms to ~2.5ms. It's not a lot, but it's something. I've profiled it several times with blackfire to confirm. The results were very consistent. Mind you, our application has quite a serious amount of routes, a little over 900.

frankdejonge · 2017-02-24T22:48:00Z

src/Symfony/Component/Routing/Matcher/Dumper/PhpMatcherDumper.php

@@ -276,7 +278,7 @@ private function compileRoute(Route $route, $name, $supportsRedirections, $paren
            } else {
                $methods = implode("', '", $methods);
                $code .= <<<EOF
-            if (!in_array(\$this->context->getMethod(), array('$methods'))) {


This removes N function calls.

frankdejonge · 2017-02-24T22:48:13Z

src/Symfony/Component/Routing/Matcher/Dumper/PhpMatcherDumper.php

@@ -266,7 +268,7 @@ private function compileRoute(Route $route, $name, $supportsRedirections, $paren
        if ($methods) {
            if (1 === count($methods)) {
                $code .= <<<EOF
-            if (\$this->context->getMethod() != '$methods[0]') {


This removes N function calls.

frankdejonge · 2017-02-24T22:48:29Z

src/Symfony/Component/Routing/Matcher/Dumper/PhpMatcherDumper.php

@@ -227,7 +229,7 @@ private function compileRoute(Route $route, $name, $supportsRedirections, $paren

        if (!count($compiledRoute->getPathVariables()) && false !== preg_match('#^(.)\^(?P<url>.*?)\$\1#'.(substr($regex, -1) === 'u' ? 'u' : ''), $regex, $m)) {
            if ($supportsTrailingSlash && substr($m['url'], -1) === '/') {
-                $conditions[] = sprintf("rtrim(\$pathinfo, '/') === %s", var_export(rtrim(str_replace('\\', '', $m['url']), '/'), true));


This removed N trim calls.

frankdejonge · 2017-02-24T22:49:29Z

src/Symfony/Component/Routing/Matcher/Dumper/PhpMatcherDumper.php

@@ -133,7 +135,7 @@ private function compileRoutes(RouteCollection $routes, $supportsRedirections)
        foreach ($groups as $collection) {
            if (null !== $regex = $collection->getAttribute('host_regex')) {
                if (!$fetchedHost) {
-                    $code .= "        \$host = \$this->context->getHost();\n\n";


This removes a reference lookup, probably hardly any impact, but in optimised code, every cycle counts, right?

fabpot · 2017-02-25T00:24:08Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher2.php

@@ -35,7 +37,7 @@ public function match($pathinfo)
        if (0 === strpos($pathinfo, '/bar')) {
            // bar
            if (preg_match('#^/bar/(?P<foo>[^/]++)$#s', $pathinfo, $matches)) {
-                if (!in_array($this->context->getMethod(), array('GET', 'HEAD'))) {
+                if (!in_array($requestMethod, array('GET', 'HEAD'))) {


Reading this line makes me think that we could even have $requestMethod set to GET when it's HEAD, so that this condition can be simplified to just if ('GET' !== $requestMethod) { WDTY?

Wouldn't we then loose the ability to distinguish the request when there's only a HEAD route defined? I see in the there's a case for adding HEAD to the accepted methods when it's a GET request, but not the other way around. So if we only have a HEAD registered, we wouldn't be able to match that anymore, right? This would only be the case if you want to support defining separate HEAD handlers, I don't know if that's currently the case.

I'll just test this out real quick.

I just tested this out. We'd loose the ability to define HEAD routes when we make that additional optimisation.

Sorry, I wasn't clear enough. My idea was to create a specific variable (different from $requestMethod, like $isLikeGetMethod or something) that holds GET when the real method is HEAD.

That shaved off a 0.2ms, which is not a lot. Was done in this commit: 0425f33

I've implemented it in such a way that it keeps current behaviour, which also became more clear to me. If there's a HEAD registered after a GET for the same route, the first route will be matched. So now there is also a variable for the special "GET is also HEAD" case. The compiled route needs to remain aware whether there was actually a HEAD clause in there initially so it uses the right request method variable, the not "special" one.

I begin to wonder though, the code generating this, and executing it, become less easy to understand. Since the boost is so enormously tiny of that last bit I suggest to consider reverting that one commit and keep the rest.

I've added the tests for the other optimisation just in case. It's 03:00 here now, so bed time. Have a good one 👍

…mparison.

hhamon · 2017-02-27T16:36:57Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher1.php

        $context = $this->context;
        $request = $this->request;
+        $requestMethod = $isLikeGetMethod = $context->getMethod();
+
+        if ($requestMethod === 'HEAD') {


Should be if ('HEAD' === $requestMethod) {

hhamon · 2017-02-27T16:37:26Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher1.php

@@ -46,8 +53,8 @@ public function match($pathinfo)

            // barhead
            if (0 === strpos($pathinfo, '/barhead') && preg_match('#^/barhead/(?P<foo>[^/]++)$#s', $pathinfo, $matches)) {
-                if (!in_array($this->context->getMethod(), array('GET', 'HEAD'))) {
-                    $allow = array_merge($allow, array('GET', 'HEAD'));
+                if ($isLikeGetMethod != 'GET') {


if ('GET' !== $isLikeGetMethod) {

hhamon · 2017-02-27T16:37:55Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher1.php

@@ -83,7 +90,7 @@ public function match($pathinfo)

            // baz5
            if (preg_match('#^/test/(?P<foo>[^/]++)/$#s', $pathinfo, $matches)) {
-                if ($this->context->getMethod() != 'POST') {
+                if ($isLikeGetMethod != 'POST') {


if ('POST' !== $isLikeGetMethod) {

hhamon · 2017-02-27T16:38:06Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher1.php

@@ -94,7 +101,7 @@ public function match($pathinfo)

            // baz.baz6
            if (preg_match('#^/test/(?P<foo>[^/]++)/$#s', $pathinfo, $matches)) {
-                if ($this->context->getMethod() != 'PUT') {
+                if ($isLikeGetMethod != 'PUT') {


if ('PUT' !== $isLikeGetMethod) {

hhamon · 2017-02-27T16:38:22Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher2.php

        $context = $this->context;
        $request = $this->request;
+        $requestMethod = $isLikeGetMethod = $context->getMethod();
+
+        if ($requestMethod === 'HEAD') {


if ('HEAD' === $isLikeGetMethod) {

hhamon · 2017-02-27T16:38:47Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher2.php

@@ -46,8 +53,8 @@ public function match($pathinfo)

            // barhead
            if (0 === strpos($pathinfo, '/barhead') && preg_match('#^/barhead/(?P<foo>[^/]++)$#s', $pathinfo, $matches)) {
-                if (!in_array($this->context->getMethod(), array('GET', 'HEAD'))) {
-                    $allow = array_merge($allow, array('GET', 'HEAD'));
+                if ($isLikeGetMethod != 'GET') {


if ('GET' !== $isLikeGetMethod) {

hhamon · 2017-02-27T16:39:01Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher2.php

@@ -91,7 +98,7 @@ public function match($pathinfo)

            // baz5
            if (preg_match('#^/test/(?P<foo>[^/]++)/$#s', $pathinfo, $matches)) {
-                if ($this->context->getMethod() != 'POST') {
+                if ($isLikeGetMethod != 'POST') {


if ('POST' !== $isLikeGetMethod) {

hhamon · 2017-02-27T16:39:08Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher2.php

@@ -102,7 +109,7 @@ public function match($pathinfo)

            // baz.baz6
            if (preg_match('#^/test/(?P<foo>[^/]++)/$#s', $pathinfo, $matches)) {
-                if ($this->context->getMethod() != 'PUT') {
+                if ($isLikeGetMethod != 'PUT') {


if ('PUT' !== $isLikeGetMethod) {

frankdejonge · 2017-02-27T16:39:15Z

@hhamon I get it, yoda-ing it now :P

hhamon · 2017-02-27T16:39:27Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher2.php

@@ -174,7 +181,7 @@ public function match($pathinfo)
            }

            // hey
-            if (rtrim($pathinfo, '/') === '/multi/hey') {
+            if ($trimmedPathinfo === '/multi/hey') {


if ('/multi/hey' === $trimmedPathinfo) {

hhamon · 2017-02-27T16:39:47Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher3.php

        $context = $this->context;
        $request = $this->request;
+        $requestMethod = $isLikeGetMethod = $context->getMethod();
+
+        if ($requestMethod === 'HEAD') {


if ('HEAD' === $requestMethod) {

frankdejonge · 2017-02-27T16:48:37Z

@hhamon I've corrected the non-yoda to yoda statement, I've also corrected the ones which I didn't change into yoda statements.

stof · 2017-02-27T16:45:56Z

src/Symfony/Component/Routing/Matcher/Dumper/PhpMatcherDumper.php

+        \$requestMethod = \$isLikeGetMethod = \$context->getMethod();
+
+        if (\$requestMethod === 'HEAD') {
+            \$isLikeGetMethod = 'GET';


the $isLikeGetMethod variable name makes me think it is a boolean

stof · 2017-02-27T16:49:03Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher2.php

-                if (!in_array($this->context->getMethod(), array('GET', 'HEAD'))) {
-                    $allow = array_merge($allow, array('GET', 'HEAD'));
+                if (!in_array($isLikeGetMethod, array('GET'))) {
+                    $allow = array_merge($allow, array('GET'));


not adding HEAD anymore to the allow array looks suspicious to me.

@stof I'm open to suggestions here. The name was given by @fabpot initially, I couldn't come up with a better name for it now. The name goes into the realm of "normalised" pretty quickly which doesn't add a lot of context.

@frankdejonge are you sure you replied to the right comment ? This looks unrelated

@stof I think github must have durped, because I looked at it when writing but now it's placed here. Super weird.

…sent.

frankdejonge · 2017-02-27T16:59:25Z

@stof I've corrected the case where only one method is present after filtering out the HEAD method.

stof · 2017-02-27T17:02:28Z

src/Symfony/Component/Routing/Tests/Fixtures/dumper/url_matcher1.php

-                if (!in_array($this->context->getMethod(), array('GET', 'HEAD'))) {
-                    $allow = array_merge($allow, array('GET', 'HEAD'));
+                if ('GET' !== $isLikeGetMethod) {
+                    $allow[] = 'GET';


Why aren't you adding HEAD anymore here ? It is an allowed method

@stof this was an optimisation proposed by @fabpot. We stream HEAD in a special way (this is current behaviour). When a HEAD request is made, we also match GET. Inverted, when we declare GET actions, we also match in HEAD. So in this normalised case we know that if something is "like get" we don't need HEAD anymore because we're we already match GET.

Can we make sure that this is properly tested? If someone else breaks this, it will be a huge bug!

@Jean85 there's an additional test case added in this PR to do just that.

…ttp method optimization, especially the HEAD case.

frankdejonge · 2017-02-27T18:32:43Z

Perhaps it would be good to rename isGetLikeMethod to methodWhereHeadMatchesGet? Might be a bit verbose, but in this case I think being explicit is preferable. WDYT @stof?

frankdejonge · 2017-02-27T18:33:20Z

I've also added another test fixture which more clearly demonstrates the effect of the method optimisation.

GuilhemN · 2017-02-28T11:19:39Z

src/Symfony/Component/Routing/Matcher/Dumper/PhpMatcherDumper.php

+        \$requestMethod = \$isLikeGetMethod = \$context->getMethod();
+        \$schema = \$context->getScheme();
+
+        if (\$requestMethod === 'HEAD') {


'HEAD' === 😉

Fixed, thanks!

javiereguiluz · 2017-02-28T11:34:47Z

src/Symfony/Component/Routing/Matcher/Dumper/PhpMatcherDumper.php

+        \$schema = \$context->getScheme();
+
+        if ('HEAD' === \$requestMethod) {
+            \$isLikeGetMethod = 'GET';


The is prefix in this variable name looks wrong. Maybe it's too late, but what if we rename $isLikeGetMethod = 'GET' to $isSafeMethod = true

We had some discussions about what a "safe method" is in HTTP, but the section 9.1.1 of RFC 2616 mentions GET and HEAD as safe methods: http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html

Or at least, rename $isLikeGetMethod = 'GET' to $isGetOrHead = true

Actually, we don't want a boolean, because then we can't perform a meaningful optimisation. We just want to have a interpreted method, which we can check against. Otherwise we'd need to do more check than less.

What about renaming it to $methodAlias or $canonicalMethod or something like that? We "can't" store a string in a $is* variable.

I like conicalMethod, a lot. I had previously opted to use methodWhereHeadMatchesGet instead. Which is a little verbose, but it does make it clear what's going on.

+1 for $canonicalMethod

I've renamed the variable to $canonicalMethod.

GuilhemN · 2017-02-28T11:39:39Z

src/Symfony/Component/Routing/Matcher/Dumper/PhpMatcherDumper.php

+                    $code .= <<<EOF
+            if ('$methods[0]' !== \$$methodVariable) {
+                \$allow[] = '$methods[0]';
+                goto $gotoname;


Has the use of the goto ever been discussed?
It seems like here we only need to reverse the conditions to get ride of it.

I'm checking this out now, if proven to be effective I'll create another PR.

@GuilhemN I suspected it to have some effect, but it did literally nothing.

frankdejonge · 2017-02-28T11:43:00Z

Tests currently seem to be failing because master is broken.

fabpot · 2017-02-28T17:26:15Z

src/Symfony/Component/Routing/Matcher/Dumper/PhpMatcherDumper.php

        \$context = \$this->context;
        \$request = \$this->request;
+        \$requestMethod = \$canonicalMethod = \$context->getMethod();
+        \$schema = \$context->getScheme();


should be $scheme here, not $schema, right?

@fabpot correct, I've fixed it.

fabpot · 2017-02-28T17:29:29Z

👍

fabpot · 2017-02-28T20:11:19Z

Thank you @frankdejonge.

…eeded function calls. (frankdejonge) This PR was squashed before being merged into the 3.3-dev branch (closes #21755). Discussion ---------- [Routing] Optimised dumped router matcher, prevent unneeded function calls. | Q | A | ------------- | --- | Branch? | master | Bug fix? | no | New feature? | no | BC breaks? | no | Deprecations? | no | Tests pass? | yes | Fixed tickets | none | License | MIT | Doc PR | does not apply The application I'm working on is fairly large. Because we had a routing issue (not caused by the framework) I looked through the dumped routing code. I spotted some easy wins. These changes brought down the time for the `match` method to run from ~ 7.5ms to ~2.5ms. It's not a lot, but it's something. I've profiled it several times with blackfire to confirm. The results were very consistent. Mind you, our application has quite a serious amount of routes, a little over 900. Commits ------- dd647ff [Routing] Optimised dumped router matcher, prevent unneeded function calls.

Optimized dumped router matcher, prevent unneeded function calls.

ea8c55a

carsonbot added the Status: Needs Review label Feb 24, 2017

Fixed CS

0d69cfe

frankdejonge commented Feb 24, 2017

View reviewed changes

fabpot reviewed Feb 25, 2017

View reviewed changes

frankdejonge added 2 commits February 25, 2017 02:33

Flipped around special GET HEAD handling for less expensive method co…

0425f33

…mparison.

Corrected tests.

56f2323

nicolas-grekas added this to the 3.3 milestone Feb 25, 2017

javiereguiluz added Enhancement Routing labels Feb 26, 2017

hhamon reviewed Feb 27, 2017

View reviewed changes

Use yoda statements.

ef6ad3a

stof reviewed Feb 27, 2017

View reviewed changes

frankdejonge added 2 commits February 27, 2017 17:57

After filtering there's also a case where only one HTTP method is pre…

44271e0

…sent.

CS

e4a9e1e

stof reviewed Feb 27, 2017

View reviewed changes

frankdejonge added 2 commits February 27, 2017 18:11

Optimise schema check as well.

2e180c6

Added a test case which more clearly demonstrates the effect of the h…

9d92c57

…ttp method optimization, especially the HEAD case.

frankdejonge changed the title ~~Optimised dumped router matcher, prevent unneeded function calls.~~ [Routing] Optimised dumped router matcher, prevent unneeded function calls. Feb 27, 2017

GuilhemN reviewed Feb 28, 2017

View reviewed changes

Yoda comparison.

f56cf9a

javiereguiluz reviewed Feb 28, 2017

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GuilhemN reviewed Feb 28, 2017

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Jean85 approved these changes Feb 28, 2017

View reviewed changes

Renamed isLikeGetMethod to canonicalMethod.

bb68154

fabpot reviewed Feb 28, 2017

View reviewed changes

It's scheme not schema.

4ab821b

fabpot closed this Feb 28, 2017

fabpot mentioned this pull request May 1, 2017

Release v3.3.0-BETA1 #22603

Merged

[Routing] Optimised dumped router matcher, prevent unneeded function calls. #21755

[Routing] Optimised dumped router matcher, prevent unneeded function calls. #21755

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frankdejonge commented Feb 24, 2017

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fabpot commented Feb 28, 2017

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