HCha/Stockfish
1
0
Fork 0
mirror of https://github.com/HChaZZY/Stockfish.git synced 2025-12-18 08:07:08 +08:00
Code Issues Packages Projects Releases Wiki Activity

Active Reparenting

Browse Source 
In Young Brothers Wait Concept (YBWC) available slaves are
booked by the split point master, then start to search below
the assigned split point and, once finished, return in idle
state waiting to be booked by another master.

This patch introduces "Active Reparenting" so that when a
slave finishes its job on the assigned split point, instead
of passively waiting to be booked, searches a suitable active
split point and reprents itselfs to that split point. Then
immediately starts to search below the split point in exactly
the same way of the others split point's slaves. This reduces
to zero the time waiting in idle loop and should increase
scalability especially whit many (8 or more) cores.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2012-04-10 18:00:31 +01:00
parent d66b765eb6
commit 44432f67d7
4 changed files with 49 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
src/thread.cpp
View File

@@ -319,6 +319,7 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta,
sp->master = master;
sp->cutoff = false;
sp->slavesMask = 1ULL << master->idx;
sp->allSlavesMask = 1ULL << master->idx;
sp->depth = depth;
sp->bestMove = *bestMove;
sp->threatMove = threatMove;
@@ -347,6 +348,7 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta,
if (threads[i]->is_available_to(master))
{
sp->slavesMask |= 1ULL << i;
sp->allSlavesMask |= 1ULL << i;
threads[i]->curSplitPoint = sp;
threads[i]->is_searching = true; // Slave leaves idle_loop()
@@ -354,7 +356,10 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta,
threads[i]->wake_up();
if (++slavesCnt + 1 >= maxThreadsPerSplitPoint) // Master is always included
{
sp->allSlavesMask = 0; // Disable reparenting to this split point
break;
}
}
lock_release(splitLock);