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arangodb
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Added sizeHint method for caches to improve warmup procedures.

This commit is contained in:
Dan Larkin 2017-05-24 13:45:53 -04:00
parent 0b8546ca98
commit 5ec026b659
3 changed files with 19 additions and 3 deletions
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9
arangod/Cache/Cache.cpp
View File

@ -115,6 +115,15 @@ uint64_t Cache::usage() {
return usage;
}
void Cache::sizeHint(uint64_t numElements) {
uint64_t numBuckets = static_cast<uint64_t>(static_cast<double>(numElements)
/ (static_cast<double>(_slotsPerBucket) * Table::idealUpperRatio));
uint32_t requestedLogSize = 0;
for (; (static_cast<uint64_t>(1) << requestedLogSize) < numBuckets;
requestedLogSize++) {}
requestMigrate(requestedLogSize);
}
std::pair<double, double> Cache::hitRates() {
double lifetimeRate = std::nan("");
double windowedRate = std::nan("");

8
arangod/Cache/Cache.h
View File

@ -97,6 +97,14 @@ class Cache : public std::enable_shared_from_this<Cache> {
//////////////////////////////////////////////////////////////////////////////
uint64_t usage();
//////////////////////////////////////////////////////////////////////////////
/// @brief Gives hint to attempt to preallocate space for an incoming load.
///
/// The parameter specifies an expected number of elements to be inserted.
/// This allows for migration to an appropriately-sized table.
//////////////////////////////////////////////////////////////////////////////
void sizeHint(uint64_t numElements);
//////////////////////////////////////////////////////////////////////////////
/// @brief Returns the cache hit-rates.
///

5
arangod/Cache/Table.h
View File

@ -39,6 +39,8 @@ namespace cache {
////////////////////////////////////////////////////////////////////////////////
class Table : public std::enable_shared_from_this<Table> {
public:
static constexpr double idealLowerRatio = 0.05;
static constexpr double idealUpperRatio = 0.33;
static const uint32_t minLogSize;
static const uint32_t maxLogSize;
static constexpr uint32_t standardLogSizeAdjustment = 6;
@ -186,9 +188,6 @@ class Table : public std::enable_shared_from_this<Table> {
uint32_t idealSize();
private:
static constexpr double idealLowerRatio = 0.05;
static constexpr double idealUpperRatio = 0.33;
State _state;
uint32_t _logSize;