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removed SpinLock around CurrentTick

This commit is contained in:
Jan Steemann 2015-07-21 15:36:50 +02:00
parent 97094b8f74
commit ecf9402b71
3 changed files with 20 additions and 53 deletions
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54
arangod/VocBase/server.cpp
View File

@ -117,13 +117,7 @@ static uint16_t ServerIdentifier = 0;
/// @brief current tick identifier (48 bit)
////////////////////////////////////////////////////////////////////////////////
static uint64_t CurrentTick = 0;
////////////////////////////////////////////////////////////////////////////////
/// @brief tick lock
////////////////////////////////////////////////////////////////////////////////
static triagens::basics::SpinLock TickLock;
static std::atomic<uint64_t> CurrentTick(0);
////////////////////////////////////////////////////////////////////////////////
/// @brief the server's global id
@ -306,30 +300,6 @@ static int DetermineServerId (TRI_server_t* server, bool checkVersion) {
return res;
}
// -----------------------------------------------------------------------------
// --SECTION-- tick functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief returns the current tick value, without using a lock
////////////////////////////////////////////////////////////////////////////////
static inline TRI_voc_tick_t GetTick (void) {
return (ServerIdentifier | (CurrentTick << 16));
}
////////////////////////////////////////////////////////////////////////////////
/// @brief updates the tick counter, without using a lock
////////////////////////////////////////////////////////////////////////////////
static inline void UpdateTick (TRI_voc_tick_t tick) {
TRI_voc_tick_t s = tick >> 16;
if (CurrentTick < s) {
CurrentTick = s;
}
}
// -----------------------------------------------------------------------------
// --SECTION-- database functions
// -----------------------------------------------------------------------------
@ -2772,8 +2742,6 @@ void TRI_GetDatabaseDefaultsServer (TRI_server_t* server,
TRI_voc_tick_t TRI_NewTickServer () {
uint64_t tick = ServerIdentifier;
SPIN_LOCKER(TickLock);
tick |= (++CurrentTick) << 16;
return tick;
@ -2784,16 +2752,15 @@ TRI_voc_tick_t TRI_NewTickServer () {
////////////////////////////////////////////////////////////////////////////////
void TRI_UpdateTickServer (TRI_voc_tick_t tick) {
SPIN_LOCKER(TickLock);
UpdateTick(tick);
}
TRI_voc_tick_t t = tick >> 16;
////////////////////////////////////////////////////////////////////////////////
/// @brief updates the tick counter, without lock - only use at startup!!
////////////////////////////////////////////////////////////////////////////////
void TRI_FastUpdateTickServer (TRI_voc_tick_t tick) {
UpdateTick(tick);
auto expected = CurrentTick.load(std::memory_order_relaxed);
// only update global tick if less than the specified value...
while (expected < t &&
! CurrentTick.compare_exchange_weak(expected, t, std::memory_order_release, std::memory_order_relaxed)) {
expected = CurrentTick.load(std::memory_order_relaxed);
}
}
////////////////////////////////////////////////////////////////////////////////
@ -2801,8 +2768,7 @@ void TRI_FastUpdateTickServer (TRI_voc_tick_t tick) {
////////////////////////////////////////////////////////////////////////////////
TRI_voc_tick_t TRI_CurrentTickServer () {
SPIN_LOCKER(TickLock);
return GetTick();
return (ServerIdentifier | (CurrentTick << 16));
}
// -----------------------------------------------------------------------------

6
arangod/VocBase/server.h
View File

@ -314,12 +314,6 @@ TRI_voc_tick_t TRI_NewTickServer (void);
void TRI_UpdateTickServer (TRI_voc_tick_t);
////////////////////////////////////////////////////////////////////////////////
/// @brief updates the tick counter, without lock - only use at startup!!
////////////////////////////////////////////////////////////////////////////////
void TRI_FastUpdateTickServer (TRI_voc_tick_t);
////////////////////////////////////////////////////////////////////////////////
/// @brief returns the current tick counter
////////////////////////////////////////////////////////////////////////////////

13
arangod/VocBase/vocbase.cpp
View File

@ -787,7 +787,11 @@ static int RenameCollection (TRI_vocbase_t* vocbase,
static bool StartupTickIterator (TRI_df_marker_t const* marker,
void* data,
TRI_datafile_t* datafile) {
TRI_FastUpdateTickServer(marker->_tick);
auto tick = static_cast<TRI_voc_tick_t*>(data);
if (marker->_tick > *tick) {
*tick = marker->_tick;
}
return true;
}
@ -856,7 +860,7 @@ static int ScanPath (TRI_vocbase_t* vocbase,
res = TRI_LoadCollectionInfo(file, &info, true);
if (res == TRI_ERROR_NO_ERROR) {
TRI_FastUpdateTickServer(info._cid);
TRI_UpdateTickServer(info._cid);
}
if (res != TRI_ERROR_NO_ERROR) {
@ -958,7 +962,10 @@ static int ScanPath (TRI_vocbase_t* vocbase,
if (iterateMarkers) {
// iterating markers may be time-consuming. we'll only do it if
// we have to
TRI_IterateTicksCollection(file, StartupTickIterator, nullptr);
TRI_voc_tick_t tick;
TRI_IterateTicksCollection(file, StartupTickIterator, &tick);
TRI_UpdateTickServer(tick);
}
LOG_DEBUG("added document collection from '%s'", file);