Detach from the UI thread the input arguments used by
the search threads so that the UI thread is able to receive
and process any command sent by the GUI while other threads
keep searching.
With this patch there is no more need to block the UI
thread after a "stop", so it is a more reliable and
robust solution than the previous patch.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Fixes an hang when playing with ponder ON. Perhaps there is still
a very small race but now it seems engine does not hang anymore.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Move global search-related variables under "Search" namespace.
As a side effect we can move uci_async_command() and
wait_for_stop_or_ponderhit() away from search.cpp
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use the starting thread to wait for GUI input and instead use
the other threads to search. The consequence is that now think()
is alwasy started on a differnt thread than the caller that
returns immediately waiting for input. This reformat greatly
simplifies the code and is more in line with the common way
to implement this feature.
As a side effect now we don't need anymore Makefile tricks
with sleep() to allow profile builds.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
If we are pondering we will stop the search only when
GUI sends "ponderhit" or "stop" commands or when we reach
maximum depth. In all the other cases we continue to search
so there is no need to verify for available time.
Also better clarify why wait_for_stop_or_ponderhit() before
to exit in some cases.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
In case there is only 1 legal move we will stop the
search at depth 10 anyway because the exclusion search
probe will fail low.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
In the "easy move" paradigm we verify if the best move has
ever changed over a good number of iterations and if the
biggest part of the searched nodes are consumed on it.
This is a kind of hacky ad indirect heuristic to deduce
if one move is much better than others.
Rewrite the early stop condition to verify directly if one
move is much better than others performing an exclusion
search.
Idea to use exclusion search for time management if form Critter.
After 12245 games at 30"+0.1
Mod vs Orig 1776 - 1775 - 8694 ELO +0 (+-3.4)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
The value returned by root search it is actually
our best value, so rename the variable to reflect this.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use do_uci_async_cmd() instead of process input commands
directly and clarify that what we are waiting for is
something that is able to raise StopRequest flag.
Also fix some stale comments in do_uci_async_cmd(). Here
we need to reset Limits.ponder only upon receiving "ponderhit".
In the case of "quit" or "stop" resetting Limits.ponder has no
effect because the search is going to be stopped anyway.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
The timer will be fired asynchronously to handle
time management flags, while other threads are
searching.
This implementation uses a thread waiting on a
timed condition variable instead of real timers.
This approach allow to reduce platform dependant
code to a minimum and also is the most portable given
that timers libraries are very different among platforms
and also the best ones are not compatible with olds
Windows.
Also retire the now unused polling code.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Instead of polling for input use a dedicated listener
thread to read commands from the GUI independently
from other threads.
To do this properly we have to delegate to the listener
all the reading from the GUI: while searching but also
while waiting for a command, like in std::getline().
So we have two possible behaviours: in-sync mode, in which
the thread mimics std::getline() and the caller blocks until
something is read from GUI, and async mode where the listener
continuously reads and processes GUI commands while other
threads are searching.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
They don't add any value given that the corresponding
table has global visibility anyhow.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
In particular add that we can have an harmless false positive
in case StopRequest or thread.cutoff_occurred() are set.
Reported by David Lee.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
As a side effect now log file is open and closed every
time it is used instead of remaining open for the whole
thinking time.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Partially revert 1036cadcec because UCI protocol
in case of multipv explicitly requires:
for the best move/pv add "multipv 1" in the string when you send the pv.
in k-best mode always send all k variants in k strings together.
Thanks to Justin Blanchard for pointing this out.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This was not clear to someone on talkchess and actually
is not trivial to understand.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Almost no increase but seems the logic thing to do.
After 16707 games 2771 - 2595 - 11341 ELO +3 (+- 3.2)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Restore old locking scheme changed with
commit 1e92df6b20.
This seems to prevent a very rare crash that occurs
once every 5-10K games.
With this patch we have no crashes after 33K games.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Now that we have just two mutually exclusive thread's states
we can repleace them by a simple boolean.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Now that Rml ordering is based on normal MovePicker logic,
apart for the ttMove that is given, we can avoid to score
all the root moves at depth 1. We only need it for easy move
detection logic, but in this case we just need to score the
first two best moves and not all the Rml set.
No regression after 6400 games
Mod vs Orig 1052 1012 4336 ELO +2 (+- 4.9)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Allocation of pawn and material hash tables should
be strictly bounded to the change of the number of
activeThreads, so move the code inside set_size().
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use proper way to detect for thread terimnation instead of
our homegrown flag.
It adds more code than it removes and adds also platform specific
code, neverthless I think is the way to go becuase Thread::TERMINATED
flag is intrinsecly racy given that when we raise it thread is still
_not_ terminated nor it can be, and also we don't want to reinvent
the (broken) wheel of thread termination detection when there is
already available the proper one.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Was used to prevent issues when creating multiple threads
on Windows, but now it seems we can remove it safely.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Now that we can split at root it happens that SendSearchedNodes
works only once at the end of the iteration, but this is useless
becuase speed info is sent anyhow toghter with the pv line.
So retire for now, waiting to find something SMP compatible.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Change qsearch() to reflect alpha update logic
of search().
To be consistent changed also moves loop condition and
futility pruning condition.
No regression after 5072 games at TC 10"+0.1
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
When calling split or we immediately return because unable to
find available slaves, or we start searching on _all_ the moves
of the node or until a cut-off occurs, so that when returning
from split we immediately leave the moves loop.
Because of this we don't need to change alpha inside split() and
we can use a signature similar to search() so to better clarify
that split() is actually a search on the remaining node's moves.
No functional change with faked split.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Allocate and initialize a new split point
out of lock becuase modified data is local to
master thread only.
Also better document why we need a lock at
the end of split().
No functional change with faked split.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
When StopRequest is raised we cannot immediately exit the
move loop but first we need to update bestValue so to avoid
assert:
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
