214 lines
8.6 KiB
Diff
214 lines
8.6 KiB
Diff
# HG changeset patch
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# User shshahma
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# Date 1474535080 25200
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# Thu Sep 22 02:04:40 2016 -0700
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# Node ID baf64c88538f477d7f5a0cf90b670108ac312375
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# Parent 62212568179b76b5ebe7b0129ddeed7b268b0bc0
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6515172, PR3346: Runtime.availableProcessors() ignores Linux taskset command
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Summary: extract processor count from sched_getaffinity mask
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Reviewed-by: dholmes, gthornbr
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diff --git a/src/os/linux/vm/globals_linux.hpp b/src/os/linux/vm/globals_linux.hpp
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--- openjdk/hotspot/src/os/linux/vm/globals_linux.hpp
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+++ openjdk/hotspot/src/os/linux/vm/globals_linux.hpp
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@@ -1,5 +1,5 @@
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/*
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- * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
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+ * Copyright (c) 2005, 2016, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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@@ -47,7 +47,10 @@
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"Load DLLs with executable-stack attribute in the VM Thread") \
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\
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product(bool, UseSHM, false, \
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- "Use SYSV shared memory for large pages")
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+ "Use SYSV shared memory for large pages") \
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+ \
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+ diagnostic(bool, PrintActiveCpus, false, \
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+ "Print the number of CPUs detected in os::active_processor_count")
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//
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// Defines Linux-specific default values. The flags are available on all
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diff --git a/src/os/linux/vm/os_linux.cpp b/src/os/linux/vm/os_linux.cpp
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--- openjdk/hotspot/src/os/linux/vm/os_linux.cpp
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+++ openjdk/hotspot/src/os/linux/vm/os_linux.cpp
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@@ -1,5 +1,5 @@
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/*
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- * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
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+ * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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@@ -104,6 +104,14 @@
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PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
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+#ifndef _GNU_SOURCE
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+ #define _GNU_SOURCE
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+ #include <sched.h>
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+ #undef _GNU_SOURCE
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+#else
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+ #include <sched.h>
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+#endif
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+
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// if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
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// getrusage() is prepared to handle the associated failure.
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#ifndef RUSAGE_THREAD
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@@ -5027,12 +5035,42 @@
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}
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};
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+static int os_cpu_count(const cpu_set_t* cpus) {
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+ int count = 0;
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+ // only look up to the number of configured processors
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+ for (int i = 0; i < os::processor_count(); i++) {
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+ if (CPU_ISSET(i, cpus)) {
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+ count++;
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+ }
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+ }
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+ return count;
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+}
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+
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+// Get the current number of available processors for this process.
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+// This value can change at any time during a process's lifetime.
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+// sched_getaffinity gives an accurate answer as it accounts for cpusets.
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+// If anything goes wrong we fallback to returning the number of online
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+// processors - which can be greater than the number available to the process.
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int os::active_processor_count() {
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- // Linux doesn't yet have a (official) notion of processor sets,
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- // so just return the number of online processors.
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- int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
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- assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
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- return online_cpus;
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+ cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
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+ int cpus_size = sizeof(cpu_set_t);
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+ int cpu_count = 0;
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+
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+ // pid 0 means the current thread - which we have to assume represents the process
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+ if (sched_getaffinity(0, cpus_size, &cpus) == 0) {
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+ cpu_count = os_cpu_count(&cpus);
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+ if (PrintActiveCpus) {
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+ tty->print_cr("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
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+ }
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+ }
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+ else {
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+ cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
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+ warning("sched_getaffinity failed (%s)- using online processor count (%d) "
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+ "which may exceed available processors", strerror(errno), cpu_count);
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+ }
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+
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+ assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check");
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+ return cpu_count;
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}
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void os::set_native_thread_name(const char *name) {
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diff --git a/test/runtime/os/AvailableProcessors.java b/test/runtime/os/AvailableProcessors.java
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new file mode 100644
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--- /dev/null
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+++ openjdk/hotspot/test/runtime/os/AvailableProcessors.java
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@@ -0,0 +1,103 @@
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+/*
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+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
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+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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+ *
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+ * This code is free software; you can redistribute it and/or modify it
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+ * under the terms of the GNU General Public License version 2 only, as
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+ * published by the Free Software Foundation.
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+ *
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+ * This code is distributed in the hope that it will be useful, but WITHOUT
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+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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+ * version 2 for more details (a copy is included in the LICENSE file that
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+ * accompanied this code).
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+ *
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+ * You should have received a copy of the GNU General Public License version
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+ * 2 along with this work; if not, write to the Free Software Foundation,
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+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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+ *
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+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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+ * or visit www.oracle.com if you need additional information or have any
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+ * questions.
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+ */
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+import java.io.File;
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+import com.oracle.java.testlibrary.ProcessTools;
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+import com.oracle.java.testlibrary.OutputAnalyzer;
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+import java.util.ArrayList;
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+
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+/*
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+ * @test
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+ * @bug 6515172
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+ * @summary Check that availableProcessors reports the correct value when running in a cpuset on linux
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+ * @requires os.family == "linux"
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+ * @library /testlibrary
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+ * @build com.oracle.java.testlibrary.*
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+ * @run driver AvailableProcessors
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+ */
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+public class AvailableProcessors {
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+
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+ static final String SUCCESS_STRING = "Found expected processors: ";
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+
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+ public static void main(String[] args) throws Throwable {
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+ if (args.length > 0)
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+ checkProcessors(Integer.parseInt(args[0]));
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+ else {
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+ // run ourselves under different cpu configurations
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+ // using the taskset command
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+ String taskset;
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+ final String taskset1 = "/bin/taskset";
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+ final String taskset2 = "/usr/bin/taskset";
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+ if (new File(taskset1).exists())
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+ taskset = taskset1;
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+ else if (new File(taskset2).exists())
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+ taskset = taskset2;
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+ else {
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+ System.out.println("Skipping test: could not find taskset command");
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+ return;
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+ }
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+
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+ int available = Runtime.getRuntime().availableProcessors();
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+
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+ if (available == 1) {
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+ System.out.println("Skipping test: only one processor available");
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+ return;
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+ }
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+
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+ // Get the java command we want to execute
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+ // Enable logging for easier failure diagnosis
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+ ProcessBuilder master =
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+ ProcessTools.createJavaProcessBuilder(false,
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+ "-XX:+UnlockDiagnosticVMOptions",
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+ "-XX:+PrintActiveCpus",
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+ "AvailableProcessors");
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+
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+ int[] expected = new int[] { 1, available/2, available-1, available };
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+
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+ for (int i : expected) {
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+ System.out.println("Testing for " + i + " processors ...");
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+ int max = i - 1;
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+ ArrayList<String> cmdline = new ArrayList<>(master.command());
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+ // prepend taskset command
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+ cmdline.add(0, "0-" + max);
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+ cmdline.add(0, "-c");
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+ cmdline.add(0, taskset);
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+ // append expected processor count
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+ cmdline.add(String.valueOf(i));
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+ ProcessBuilder pb = new ProcessBuilder(cmdline);
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+ System.out.println("Final command line: " +
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+ ProcessTools.getCommandLine(pb));
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+ OutputAnalyzer output = ProcessTools.executeProcess(pb);
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+ output.shouldContain(SUCCESS_STRING);
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+ }
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+ }
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+ }
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+
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+ static void checkProcessors(int expected) {
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+ int available = Runtime.getRuntime().availableProcessors();
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+ if (available != expected)
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+ throw new Error("Expected " + expected + " processors, but found "
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+ + available);
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+ else
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+ System.out.println(SUCCESS_STRING + available);
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+ }
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+}
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