Changeset 276855 in webkit

Timestamp:

Apr 30, 2021 2:50:21 PM (3 years ago)

Author:

fpizlo@apple.com

Message:

Make the JIT pool smaller on AS
​https://bugs.webkit.org/show_bug.cgi?id=225249

Reviewed by Saam Barati.

This adds three related features:

• Makes it easy to dump where the JIT pool was allocated.

• Makes it possible to override the JIT pool size with Options even with jump islands.

• Changes the default JIT pool size on AS to 512MB.

Estimated 2% speed-up on JetStream2, 1.5% speed-up on Speedometer2.

• jit/ExecutableAllocator.cpp:

(JSC::initializeJITPageReservation):

• runtime/OptionsList.h:

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• jit/ExecutableAllocator.cpp (modified) (9 diffs)
• runtime/OptionsList.h (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2021-04-30  Filip Pizlo  <fpizlo@apple.com>
+
+        Make the JIT pool smaller on AS
+        https://bugs.webkit.org/show_bug.cgi?id=225249
+
+        Reviewed by Saam Barati.
+
+        This adds three related features:
+
+        - Makes it easy to dump where the JIT pool was allocated.
+
+        - Makes it possible to override the JIT pool size with Options even with jump islands.
+
+        - Changes the default JIT pool size on AS to 512MB.
+
+        Estimated 2% speed-up on JetStream2, 1.5% speed-up on Speedometer2.
+
+        * jit/ExecutableAllocator.cpp:
+        (JSC::initializeJITPageReservation):
+        * runtime/OptionsList.h:
+
 2021-04-29  Saam Barati  <sbarati@apple.com>
 

trunk/Source/JavaScriptCore/jit/ExecutableAllocator.cpp

@@ -1 +1 @@
 /*
- * Copyright (C) 2008-2020 Apple Inc. All rights reserved.
+ * Copyright (C) 2008-2021 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -96 +96 @@
 #elif CPU(ARM64)
 #if ENABLE(JUMP_ISLANDS)
-static constexpr size_t fixedExecutableMemoryPoolSize = 1 * GB;
+static constexpr size_t fixedExecutableMemoryPoolSize = 512 * MB;
 // These sizes guarantee that any jump within an island can jump forwards or backwards
 // to the adjacent island in a single instruction.
 static constexpr size_t regionSize = 112 * MB;
 static constexpr size_t islandRegionSize = 16 * MB;
-static constexpr size_t numberOfRegions = fixedExecutableMemoryPoolSize / regionSize;
+static constexpr size_t maxNumberOfRegions = fixedExecutableMemoryPoolSize / regionSize;
 static constexpr size_t islandSizeInBytes = 4;
 static constexpr size_t maxIslandsPerRegion = islandRegionSize / islandSizeInBytes;
@@ -332 +332 @@
 
     reservation.size = fixedExecutableMemoryPoolSize;
-#if !ENABLE(JUMP_ISLANDS)
-    // FIXME: Consider making jump islands work with Options::jitMemoryReservationSize
-    // https://bugs.webkit.org/show_bug.cgi?id=209037
+
     if (Options::jitMemoryReservationSize())
         reservation.size = Options::jitMemoryReservationSize();
-#endif
+
     reservation.size = std::max(roundUpToMultipleOf(pageSize(), reservation.size), pageSize() * 2);
 
@@ -352 +350 @@
 
     reservation.pageReservation = tryCreatePageReservation(reservation.size);
+
+    if (Options::verboseExecutablePoolAllocation())
+        dataLog(getpid(), ": Got executable pool reservation at ", RawPointer(reservation.pageReservation.base()), "...", RawPointer(bitwise_cast<char*>(reservation.pageReservation.base()) + reservation.pageReservation.size()), ", while I'm at ", RawPointer(bitwise_cast<void*>(initializeJITPageReservation)), "\n");
+    
     if (reservation.pageReservation) {
         ASSERT(reservation.pageReservation.size() == reservation.size);
@@ -398 +400 @@
     FixedVMPoolExecutableAllocator()
 #if ENABLE(JUMP_ISLANDS)
-        : m_allocators(constructFixedSizeArrayWithArguments<RegionAllocator, numberOfRegions>(*this))
+        : m_allocators(constructFixedSizeArrayWithArguments<RegionAllocator, maxNumberOfRegions>(*this))
+        , m_numAllocators(maxNumberOfRegions)
 #else
         : m_allocator(*this)
@@ -409 +412 @@
             uintptr_t start = bitwise_cast<uintptr_t>(memoryStart());
             uintptr_t reservationEnd = bitwise_cast<uintptr_t>(memoryEnd());
-            for (size_t i = 0; i < numberOfRegions; ++i) {
-                RELEASE_ASSERT(start < reservationEnd);
+            for (size_t i = 0; i < maxNumberOfRegions; ++i) {
+                RELEASE_ASSERT(start < reservationEnd || Options::jitMemoryReservationSize());
+                if (start >= reservationEnd) {
+                    m_numAllocators = i;
+                    break;
+                }
                 m_allocators[i].m_start = tagCodePtr<ExecutableMemoryPtrTag>(bitwise_cast<void*>(start));
                 m_allocators[i].m_end = tagCodePtr<ExecutableMemoryPtrTag>(bitwise_cast<void*>(start + regionSize));
                 if (m_allocators[i].end() > reservationEnd) {
                     // We may have taken a page for the executable only copy thunk.
-                    RELEASE_ASSERT(i == numberOfRegions - 1);
+                    RELEASE_ASSERT(i == maxNumberOfRegions - 1 || Options::jitMemoryReservationSize());
                     m_allocators[i].m_end = tagCodePtr<ExecutableMemoryPtrTag>(bitwise_cast<void*>(reservationEnd));
                 }
@@ -451 +458 @@
         unsigned start = 0;
         if (Options::useRandomizingExecutableIslandAllocation())
-            start = cryptographicallyRandomNumber() % m_allocators.size();
+            start = cryptographicallyRandomNumber() % m_numAllocators;
 
         unsigned i = start;
@@ -458 +465 @@
             if (RefPtr<ExecutableMemoryHandle> result = allocator.allocate(locker, sizeInBytes))
                 return result;
-            i = (i + 1) % m_allocators.size();
+            i = (i + 1) % m_numAllocators;
             if (i == start)
                 break;
@@ -833 +840 @@
     PageReservation m_reservation;
 #if ENABLE(JUMP_ISLANDS)
-    std::array<RegionAllocator, numberOfRegions> m_allocators;
+    std::array<RegionAllocator, maxNumberOfRegions> m_allocators;
+    unsigned m_numAllocators;
     RedBlackTree<Islands, void*> m_islandsForJumpSourceLocation;
 #else

trunk/Source/JavaScriptCore/runtime/OptionsList.h

@@ -533 +533 @@
     v(Bool, useSharedArrayBuffer, false, Normal, nullptr) \
     v(Bool, useTopLevelAwait, true, Normal, "allow the await keyword at the top level of a module.") \
+    v(Bool, dumpLinking, false, Normal, nullptr) \
+    v(Bool, verifySame4GBLink, false, Normal, nullptr) \
+    v(Bool, verboseExecutablePoolAllocation, false, Normal, nullptr) \