diff options
author | Erik Verbruggen <erik.verbruggen@digia.com> | 2016-03-03 15:06:25 +0100 |
---|---|---|
committer | Erik Verbruggen <erik.verbruggen@theqtcompany.com> | 2016-03-08 09:37:40 +0000 |
commit | ec3b4cf7a5de9a4ead73f09c3d7a02421b29f805 (patch) | |
tree | 38f816e8ca1219c81bb5419ef1c7ef60209630a1 /src/particles/qquickparticlesystem_p.h | |
parent | 350a74ec69b535df07ad7ca45415090749c75293 (diff) |
Particles: replace a QSet<int> with a bit vector for group data.
The reusableIndexes represented a "free-list". Now the allocation
behavior in QQuickParticleGroupData::setSize was to grow by (large)
chunks. That means that as soon setSize was called, a (big) number of
hash entries was created, which are drained over time. This memory would
stay around (and probably unused) as long as the group was alive.
By using a bit vector, the amount of memory is much more compressed,
and finding an entry takes less time. The FreeList "caches" the next
free entry, because allocation and de-allocation behavior is that they
occur bunches: allocate a number of particles, use them, allocate the
same number.
Test case: samegame, 1 player, click 1 set of 3 stones, quit.
QQuickParticleSystem::emittersChanged(), before patch:
- 21 instr. inclusive, 15M in QQuickParticleGroupData::setSize
- 23,000 calls to QHashData::allocateNode
after:
- 13M instr. inclusive, 7M in QQuickParticleGroupData::setSize
- 0 calls to QHashData::allocateNode
Change-Id: If35ea5ed9b29129f210638f6f59275a24eb6afdc
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
Diffstat (limited to 'src/particles/qquickparticlesystem_p.h')
-rw-r--r-- | src/particles/qquickparticlesystem_p.h | 62 |
1 files changed, 61 insertions, 1 deletions
diff --git a/src/particles/qquickparticlesystem_p.h b/src/particles/qquickparticlesystem_p.h index fcdd027a54..182fc6aed6 100644 --- a/src/particles/qquickparticlesystem_p.h +++ b/src/particles/qquickparticlesystem_p.h @@ -61,6 +61,7 @@ #include <QAbstractAnimation> #include <QtQml/qqml.h> #include <private/qv8engine_p.h> //For QQmlV4Handle +#include <private/qv4util_p.h> #include "qtquickparticlesglobal_p.h" QT_BEGIN_NAMESPACE @@ -134,6 +135,65 @@ private: }; class Q_QUICKPARTICLES_PRIVATE_EXPORT QQuickParticleGroupData { + class FreeList + { + public: + FreeList() + : firstUnused(UINT_MAX) + , allocated(0) + {} + + void resize(int newSize) + { + Q_ASSERT(newSize >= 0); + int oldSize = isUnused.size(); + isUnused.resize(newSize, true); + if (newSize > oldSize) { + if (firstUnused == UINT_MAX) { + firstUnused = oldSize; + } else { + firstUnused = std::min(firstUnused, unsigned(oldSize)); + } + } else if (firstUnused >= unsigned(newSize)) { + firstUnused = UINT_MAX; + } + } + + void free(int index) + { + isUnused.setBit(index); + firstUnused = std::min(firstUnused, unsigned(index)); + --allocated; + } + + int count() const + { return allocated; } + + bool hasUnusedEntries() const + { return firstUnused != UINT_MAX; } + + int alloc() + { + if (hasUnusedEntries()) { + int nextFree = firstUnused; + isUnused.clearBit(firstUnused); + firstUnused = isUnused.findNext(firstUnused, true, false); + if (firstUnused >= unsigned(isUnused.size())) { + firstUnused = UINT_MAX; + } + ++allocated; + return nextFree; + } else { + return -1; + } + } + + private: + QV4::BitVector isUnused; + unsigned firstUnused; + int allocated; + }; + public: // types typedef int ID; enum { InvalidID = -1, DefaultGroupID = 0 }; @@ -154,7 +214,7 @@ public: //TODO: Refactor particle data list out into a separate class QVector<QQuickParticleData*> data; - QSet<int> reusableIndexes; + FreeList freeList; QQuickParticleDataHeap dataHeap; bool recycle(); //Force recycling round, returns true if all indexes are now reusable |