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[dxvk] Optimize barrier hash table lookup

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Using a prime as the table size is technically better, but that
integer division kind of hurts when we're spamming look-ups.
This commit is contained in:
Philip Rebohle 2022-08-10 23:08:28 +02:00
parent ad020c23f9
commit 8aae9c85bb
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GPG Key ID: C8CC613427A31C99
1 changed files with 15 additions and 8 deletions
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23
src/dxvk/dxvk_barrier.h
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@ -357,22 +357,28 @@ namespace dxvk {
uint64_t m_version = 1ull;
uint64_t m_used = 0ull;
size_t m_indexMask = 0;
std::vector<ListEntry> m_list;
std::vector<HashEntry> m_hashMap;
static size_t computeHash(K key) {
return size_t(uint64_t(key));
size_t hash = size_t(key) * 93887;
return hash ^ (hash >> 16);
}
size_t computeSize() const {
return m_indexMask
? m_indexMask + 1
: 0;
}
size_t computeIndex(K key) const {
return computeHash(key) % m_hashMap.size();
return computeHash(key) & (m_indexMask);
}
size_t advanceIndex(size_t index) const {
size_t size = m_hashMap.size();
size_t next = index + 1;
return next < size ? next : 0;
return (index + 1) & m_indexMask;
}
HashEntry* findHashEntry(K key) {
@ -416,7 +422,7 @@ namespace dxvk {
}
void growHashMap(size_t newSize) {
size_t oldSize = m_hashMap.size();
size_t oldSize = computeSize();
m_hashMap.resize(newSize);
// Relocate hash entries in place
@ -436,14 +442,15 @@ namespace dxvk {
}
m_version += 1;
m_indexMask = newSize - 1;
}
void growHashMapBeforeInsert() {
// Allow a load factor of 0.7 for performance reasons
size_t oldSize = m_hashMap.size();
size_t oldSize = computeSize();
if (10 * m_used >= 7 * oldSize) {
size_t newSize = oldSize ? (oldSize * 2 + 5) : 37;
size_t newSize = oldSize ? oldSize * 2 : 64;
growHashMap(newSize);
}
}