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<dl class="meta">
<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/200444">200444</a></dd>
<dt>Author</dt> <dd>fpizlo@apple.com</dd>
<dt>Date</dt> <dd>2016-05-04 17:18:13 -0700 (Wed, 04 May 2016)</dd>
</dl>
<h3>Log Message</h3>
<pre>Add HLE locks and synchronic TTAS locks to the ToyLocks benchmark suite
https://bugs.webkit.org/show_bug.cgi?id=157367
Rubber stamped by Benjamin Poulain.
Turns out they are both a lot slower than WTF::Lock. The HLE lock is written according to Intel's
documentation. The synchronic lock follows the algorithm of the "ttas_lock" in the synchronic
test.hpp.
* benchmarks/ToyLocks.h:</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceWTFChangeLog">trunk/Source/WTF/ChangeLog</a></li>
<li><a href="#trunkSourceWTFbenchmarksToyLocksh">trunk/Source/WTF/benchmarks/ToyLocks.h</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceWTFChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/WTF/ChangeLog (200443 => 200444)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WTF/ChangeLog 2016-05-05 00:14:46 UTC (rev 200443)
+++ trunk/Source/WTF/ChangeLog 2016-05-05 00:18:13 UTC (rev 200444)
</span><span class="lines">@@ -1,5 +1,18 @@
</span><span class="cx"> 2016-05-04 Filip Pizlo <fpizlo@apple.com>
</span><span class="cx">
</span><ins>+ Add HLE locks and synchronic TTAS locks to the ToyLocks benchmark suite
+ https://bugs.webkit.org/show_bug.cgi?id=157367
+
+ Rubber stamped by Benjamin Poulain.
+
+ Turns out they are both a lot slower than WTF::Lock. The HLE lock is written according to Intel's
+ documentation. The synchronic lock follows the algorithm of the "ttas_lock" in the synchronic
+ test.hpp.
+
+ * benchmarks/ToyLocks.h:
+
+2016-05-04 Filip Pizlo <fpizlo@apple.com>
+
</ins><span class="cx"> Add a few more WTF locking benchmarks
</span><span class="cx"> https://bugs.webkit.org/show_bug.cgi?id=157365
</span><span class="cx">
</span></span></pre></div>
<a id="trunkSourceWTFbenchmarksToyLocksh"></a>
<div class="modfile"><h4>Modified: trunk/Source/WTF/benchmarks/ToyLocks.h (200443 => 200444)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WTF/benchmarks/ToyLocks.h 2016-05-05 00:14:46 UTC (rev 200443)
+++ trunk/Source/WTF/benchmarks/ToyLocks.h 2016-05-05 00:18:13 UTC (rev 200444)
</span><span class="lines">@@ -32,6 +32,10 @@
</span><span class="cx"> #include <wtf/ParkingLot.h>
</span><span class="cx"> #include <wtf/WordLock.h>
</span><span class="cx">
</span><ins>+#if defined(EXTRA_LOCKS) && EXTRA_LOCKS
+#include <synchronic>
+#endif
+
</ins><span class="cx"> namespace {
</span><span class="cx">
</span><span class="cx"> unsigned toyLockSpinLimit = 40;
</span><span class="lines">@@ -92,6 +96,83 @@
</span><span class="cx"> Atomic<unsigned> m_lock;
</span><span class="cx"> };
</span><span class="cx">
</span><ins>+#if defined(EXTRA_LOCKS) && EXTRA_LOCKS
+class TransactionalSpinLock {
+public:
+ TransactionalSpinLock()
+ {
+ m_lock = 0;
+ }
+
+ void lock()
+ {
+ for (;;) {
+ unsigned char result;
+ unsigned expected = 0;
+ unsigned desired = 1;
+ asm volatile (
+ "xacquire; lock; cmpxchgl %3, %2\n\t"
+ "sete %1"
+ : "+a"(expected), "=q"(result), "+m"(m_lock)
+ : "r"(desired)
+ : "memory");
+ if (result)
+ return;
+ std::this_thread::yield();
+ }
+ }
+
+ void unlock()
+ {
+ asm volatile (
+ "xrelease; movl $0, %0"
+ :
+ : "m"(m_lock)
+ : "memory");
+ }
+
+ bool isLocked() const
+ {
+ return m_lock;
+ }
+
+private:
+ unsigned m_lock;
+};
+
+class SynchronicLock {
+public:
+ SynchronicLock()
+ : m_locked(0)
+ {
+ }
+
+ void lock()
+ {
+ for (;;) {
+ int state = 0;
+ if (m_locked.compare_exchange_weak(state, 1, std::memory_order_acquire))
+ return;
+ m_sync.wait_for_change(m_locked, state, std::memory_order_relaxed);
+ }
+ }
+
+ void unlock()
+ {
+ m_sync.notify_one(m_locked, 0, std::memory_order_release);
+ }
+
+ bool isLocked()
+ {
+ return m_locked.load();
+ }
+
+private:
+ std::atomic<int> m_locked;
+ std::experimental::synchronic<int> m_sync;
+};
+#endif
+
</ins><span class="cx"> template<typename StateType>
</span><span class="cx"> class BargingLock {
</span><span class="cx"> public:
</span><span class="lines">@@ -392,6 +473,12 @@
</span><span class="cx"> Benchmark::template run<YieldSpinLock>("YieldSpinLock");
</span><span class="cx"> if (!strcmp(what, "pausespinlock") || !strcmp(what, "all"))
</span><span class="cx"> Benchmark::template run<PauseSpinLock>("PauseSpinLock");
</span><ins>+#if defined(EXTRA_LOCKS) && EXTRA_LOCKS
+ if (!strcmp(what, "transactionalspinlock") || !strcmp(what, "all"))
+ Benchmark::template run<TransactionalSpinLock>("TransactionalSpinLock");
+ if (!strcmp(what, "synchroniclock") || !strcmp(what, "all"))
+ Benchmark::template run<SynchronicLock>("SynchronicLock");
+#endif
</ins><span class="cx"> if (!strcmp(what, "wordlock") || !strcmp(what, "all"))
</span><span class="cx"> Benchmark::template run<WordLock>("WTFWordLock");
</span><span class="cx"> if (!strcmp(what, "lock") || !strcmp(what, "all"))
</span></span></pre>
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