Add processor affinity setting "--cpu-fraction".

base/DatabaseInstaller.php

@@ -15,7 +15,9 @@ final class DatabaseInstaller {
   private ?string $username;
   private ?string $password = null;
 
-  public function __construct(private PerfOptions $options): void {}
+  public function __construct(private PerfOptions $options): void {
+    $this->configureMysqlAffinity();
+  }
 
   public function getUsername(): ?string {
     return $this->username ? $this->username : $this->databaseName;
@@ -35,6 +37,14 @@ public function setDumpFile(string $dump_file): this {
     return $this;
   }
 
+  public function configureMysqlAffinity(): void {
+    if ($this->options->cpuBind) {
+      exec("sudo taskset -acp ".$this->options->helperProcessors." `pgrep mysqld`");
+      print "You need to restart mysql after the benchmarks to remove the ";
+      print "processor affinity.\n";
+    }
+  }
+
   public function installDatabase(): bool {
     $db = $this->databaseName;
     $dump = $this->dumpFile;

base/HHVMDaemon.php

@@ -64,6 +64,9 @@ protected function getTarget(): PerfTarget {
 
   <<__Override>>
   protected function getArguments(): Vector<string> {
+    if ($this->options->cpuBind) {
+      $this->cpuRange = $this->options->daemonProcessors;
+    }
     $args = Vector {
       '-m',
       'server',

base/NginxDaemon.php

@@ -110,6 +110,9 @@ protected function getPidFilePath(): string {
 
   <<__Override>>
   protected function getArguments(): Vector<string> {
+    if ($this->options->cpuBind) {
+      $this->cpuRange = $this->options->helperProcessors;
+    }
     return Vector {
       '-c',
       $this->getGeneratedConfigFile(),

base/PHP5Daemon.php

@@ -72,6 +72,9 @@ public function start(): void {
   }
 
   protected function getArguments(): Vector<string> {
+    if ($this->options->cpuBind) {
+      $this->cpuRange = $this->options->daemonProcessors;
+    }
     if ($this->options->fpm) {
       echo 'Creating PHP FPM config';
       $path = $this->options->tempDir.'/php-fpm.conf';

base/PerfOptions.php

@@ -42,6 +42,10 @@ final class PerfOptions {
   public ?string $dbUsername;
   public ?string $dbPassword;
 
+  public bool $cpuBind = false;
+  public ?string $daemonProcessors;
+  public ?string $helperProcessors;
+
   public bool $fetchResources = false;
   public bool $forceInnodb = false;
   public bool $skipSanityCheck = false;
@@ -146,6 +150,7 @@ public function __construct(Vector<string> $argv) {
       'setUpTest:',
       'db-username:',
       'db-password:',
+      'cpu-fraction:',
       'tearDownTest:',
       'i-am-not-benchmarking',
       'hhvm-extra-arguments:',
@@ -255,6 +260,17 @@ public function __construct(Vector<string> $argv) {
     $this->proxygen = !$this->getBool('no-proxygen');
     $this->applyPatches = $this->getBool('apply-patches');
 
+    $fraction = $this->getFloat('cpu-fraction', 1.0);
+    if ($fraction !== 1.0) {
+      $this->cpuBind = true;
+      $output = [];
+      exec('nproc', $output);
+      $numProcessors = (int)($output[0]);
+      $numDaemonProcessors = (int)($numProcessors * $fraction);
+      $this->helperProcessors = "$numDaemonProcessors-$numProcessors";
+      $this->daemonProcessors = "0-$numDaemonProcessors";
+    }
+
     $this->precompile = !$this->getBool('no-repo-auth');
     $this->filecache = $this->precompile && !$this->getBool('no-file-cache');
     $this->pcreCache = $this->getNullableString('pcre-cache');

base/Process.php

@@ -14,6 +14,7 @@ abstract class Process {
   protected ?resource $stdin;
   protected ?resource $stdout;
   protected ?string $command;
+  protected ?string $cpuRange = null;
   protected bool $suppress_stdout = false;
 
   private static Vector<Process> $processes = Vector {};
@@ -54,6 +55,11 @@ public function startWorker(
     if ($this->suppress_stdout) {
       $this->command .= ' >/dev/null';
     }
+
+    if ($this->cpuRange !== null) {
+      $this->command = 'taskset -c '.$this->cpuRange.' '.$this->command;
+    }
+
     $use_pipe = ($outputFileName === null);
     $spec =
       [

base/Siege.php

@@ -84,6 +84,9 @@ public function getExecutablePath(): string {
 
   <<__Override>>
   protected function getArguments(): Vector<string> {
+    if ($this->options->cpuBind) {
+      $this->cpuRange = $this->options->helperProcessors;
+    }
     $urls_file = tempnam($this->options->tempDir, 'urls');
     $urls = file_get_contents($this->target->getURLsFile());
     $urls =

batch-run.json.example

@@ -44,6 +44,10 @@
   },
   "settings": {
     "username": "root",
-    "password": "root"
+    "password": "root",
+    "options": [
+      "cpu-fraction=0.5",
+      "i-am-not-benchmarking"
+    ]
   }
 }

batch-run.php

@@ -143,6 +143,13 @@ function batch_get_single_run(
   $argv->addAll($runtime['args']);
   $argv[] = '--'.$target['name'];
 
+  foreach ($target['settings'] as $name => $value) {
+    if ($name === 'options') {
+      foreach ((array)$value as $v) {
+        $argv[] = '--'.$v;
+      }
+    }
+  }
   $options = new PerfOptions($argv);
   switch ($runtime['type']) {
     case BatchRuntimeType::HHVM:

scripts/setup.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-sudo apt-get -y install nginx unzip mysql-server
+sudo apt-get -y install nginx unzip mysql-server util-linux coreutils
 sudo apt-get -y install autotools-dev
 sudo apt-get -y install autoconf
 sudo apt-get -y install software-properties-common build-essential