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uct on gpu
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Daniel Shawul



Joined: 14 Mar 2006
Posts: 2268
Location: Ethiopia
PostPost subject: Re: uct on gpu    Posted: Sat Feb 25, 2012 8:30 pm Reply to topic Reply with quote
Quote:

What side effects (if any) do you think will the block simulation have on UCT? For perft approximations we did before, I used 2 simulations per call but the results were not added up.

I think this has a significant effect for gpu uct. The problem was so severe I had to fix it through modification of the UCT formula for node selection. The problem is if one multi-processor takes a node to simulate, it sure is not going to return just after one simulation (which btw is the case for cpu UCT). It could produce 8192 simulation for instance. In fact all the multi processors (14 of them) will follow the same path to that node as there is no randomness in the selection formula!! That was very bad indeed and it resulted in an effect where the whole device works only one node at a time and then move to another,and another... I fixed this problem by adding a workers counter for each node that is incremented and decremented atomically. Then during selection , nodes that have been grabed already are given lower priorities. For example univisted nodes will have a score:
Code:

score = FPU - (n->workers / nBlocks)

Same modification to those nodes which are visited.
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Subject Author Date/Time
uct on gpu Daniel Shawul Fri Feb 24, 2012 5:52 am
      Re: uct on gpu Srdja Matovic Fri Feb 24, 2012 8:17 am
      Re: uct on gpu Srdja Matovic Fri Feb 24, 2012 8:45 am
            Re: uct on gpu Daniel Shawul Fri Feb 24, 2012 1:00 pm
                  Re: uct on gpu Srdja Matovic Fri Feb 24, 2012 1:44 pm
                        Re: uct on gpu Daniel Shawul Fri Feb 24, 2012 2:28 pm
                              Re: uct on gpu Srdja Matovic Fri Feb 24, 2012 3:04 pm
                                    Re: uct on gpu Daniel Shawul Fri Feb 24, 2012 3:53 pm
                  Re: uct on gpu david nash Sun Feb 26, 2012 12:42 am
                        Re: uct on gpu Daniel Shawul Thu Mar 08, 2012 1:26 pm
      Re: uct on gpu Daniel Shawul Sat Feb 25, 2012 8:30 pm
      100x speed up Daniel Shawul Mon Feb 27, 2012 8:02 pm
            Re: 100x speed up Robert Hyatt Thu Mar 15, 2012 2:13 pm
                  Re: 100x speed up Daniel Shawul Thu Mar 15, 2012 3:24 pm
                        Re: 100x speed up Robert Hyatt Thu Mar 15, 2012 4:35 pm
                              Re: 100x speed up Daniel Shawul Thu Mar 15, 2012 5:11 pm
                                    Table Daniel Shawul Thu Mar 15, 2012 5:51 pm
                                    Re: 100x speed up Robert Hyatt Thu Mar 15, 2012 7:36 pm
                                          Re: 100x speed up Daniel Shawul Thu Mar 15, 2012 8:21 pm
      Re: uct on gpu Daniel Shawul Thu Mar 08, 2012 1:08 pm
      uct for chess Daniel Shawul Mon Mar 12, 2012 10:30 pm
            Re: uct for chess Karlo Bala Jr. Mon Mar 12, 2012 11:14 pm
                  Re: uct for chess Daniel Shawul Tue Mar 13, 2012 12:13 am
                        Re: uct for chess Karlo Bala Jr. Tue Mar 13, 2012 12:52 pm
            Re: uct for chess Srdja Matovic Tue Mar 13, 2012 8:08 pm
                  Re: uct for chess Daniel Shawul Tue Mar 13, 2012 9:43 pm
                        Re: uct for chess Daniel Shawul Wed Mar 14, 2012 2:21 am
                        Re: uct for chess Srdja Matovic Wed Mar 14, 2012 11:56 am
                              Re: uct for chess Daniel Shawul Wed Mar 14, 2012 12:46 pm
                                    Re: uct for chess Srdja Matovic Wed Mar 14, 2012 1:00 pm
                        Re: uct for chess - move gen speedup by vector datatypes Srdja Matovic Mon Mar 19, 2012 3:04 pm
                              Re: uct for chess - move gen speedup by vector datatypes Daniel Shawul Mon Mar 19, 2012 8:01 pm
                                    Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Mon Mar 19, 2012 8:43 pm
                                          Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Mon Mar 19, 2012 9:01 pm
                                                Re: uct for chess - move gen speedup by vector datatypes Daniel Shawul Mon Mar 19, 2012 10:01 pm
                                                      Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Tue Mar 20, 2012 12:59 am
                                                            Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Tue Mar 20, 2012 1:04 am
                                                            Re: uct for chess - move gen speedup by vector datatypes Daniel Shawul Tue Mar 20, 2012 2:40 am
                                                                  Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Tue Mar 20, 2012 1:07 pm
                                                                        Re: uct for chess - MCS, YBW and 32 bit move gen Srdja Matovic Tue Mar 20, 2012 2:37 pm
                                                                              Re: uct for chess - MCS, YBW and 32 bit move gen Vincent Diepeveen Wed Mar 21, 2012 4:39 pm
                                                                                    Re: uct for chess - MCS, YBW and 32 bit move gen Srdja Matovic Wed Mar 21, 2012 5:53 pm
                                                                        Re: uct for chess - move gen speedup by vector datatypes Daniel Shawul Tue Mar 20, 2012 3:18 pm
                                                                              Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Wed Mar 21, 2012 2:13 pm
                                                                                    Re: uct for chess - move gen speedup by vector datatypes Daniel Shawul Wed Mar 21, 2012 4:00 pm
                              Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Mon Mar 19, 2012 8:33 pm
                                    Re: uct for chess - move gen speedup by vector datatypes Srdja Matovic Mon Mar 19, 2012 9:30 pm
                                          Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Tue Mar 20, 2012 12:54 am
                                          Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Tue Mar 20, 2012 12:45 pm
                              Re: uct for chess - move gen speedup by vector datatypes Srdja Matovic Tue Mar 20, 2012 2:38 am
                                    Re: uct for chess - move gen speedup by vector datatypes Vincent Diepeveen Tue Mar 20, 2012 1:13 pm
                                          Re: uct for chess - move gen speedup by vector datatypes Srdja Matovic Tue Mar 20, 2012 1:43 pm
                                                Re: uct for chess - move gen performance killers Srdja Matovic Tue Mar 20, 2012 4:45 pm
            intrinsic popcnt Daniel Shawul Wed Mar 14, 2012 5:21 am
                  Re: intrinsic popcnt Daniel Shawul Wed Mar 14, 2012 5:50 am
                        Re: intrinsic popcnt Robert Hyatt Thu Mar 15, 2012 5:12 pm
      Re: uct on gpu Vincent Diepeveen Thu Mar 15, 2012 8:14 pm
            Re: uct on gpu Daniel Shawul Thu Mar 15, 2012 8:27 pm
                  Re: uct on gpu Vincent Diepeveen Sat Mar 17, 2012 1:17 pm
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