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YBWC: Active Reparenting
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Vincent Diepeveen



Joined: 09 Mar 2006
Posts: 1738
Location: The Netherlands

PostPost subject: Re: YBWC: Active Reparenting    Posted: Tue Apr 10, 2012 6:23 pm Reply to topic Reply with quote

CPU's that don't cause a cutoff at this node yet do unsubscribe themselves from this search and basically are idle, i called that cpu's calling AbortMe().

CPU's that cause either a research (PV) or fail high at this node, causing all other cpu's to get aborted, that's what i described as an AbortFailHigh().

CPU's that call AbortMe() yet then are idle because they own the specific 'recursionstack' and which activelly go search THEMSELVE higher in the search tree (so not lower which is what Crafty is doing) and/or at other CPU's stealing work there, that's basically a DTS feature as invented by Bob.
From what i understood - long time ago - in DTS cpu's actively search themselves for a job.

It does give a good speedup. So from algorithmic viewpoint it's a good thing.

Note i'm not a fan of this at modern hardware as it doesn't scale IMHO, yet YMMV there as Diep of course is in a bigger luxury position there as it doesn't have a recursive search at all, so it doesn't have this problem.

It's not clear to me whether you can claim a new name for this. Have to ask Bob careful for that - again with Diep i don't need a solution like this as it's in the first place already having a superior design there.

At the cluster though i need creative stuff to solve it all as it has more limitations of course with remote nodes. So i'm already looking there to memory migration, yet again in a manner that idle cpu's do not search themselves for a job Smile

The guy who really has been busy with that is Bob.

mcostalba wrote:
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.

I have pushed a patch that introduces what I have called "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 reparents itself 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 _could_ increase scalability especially with many (8 or more) cores, at least this is the idea.

Unfortunately I don't have access to any 8-core machine to test the patch, so the only thing I can do on my QUAD (and I have already started) is to test for regressions. So here we come to the reason of this post: in case someone has an 8-core (or better) computer and is willing to test this patch please drop me a pm. Just to give you an idea I was thinking to test along these lines:

Code:

- Computer fully dedicated for this test, no background activity during the whole test
- At least 8 cores CPU
- At least 1 minute per game
- At least 1000 games
- No pondering


Thanks in advance for any help.
Marco


P.S: Patch is below. It is not difficult to understand for people knowing (read, with hands-on coding experience) the subject:
https://github.com/mcostalba/Stockfish/commit/44432f67d724573d0f6e3cfea6165c9b1d125d72


Last edited by Vincent Diepeveen on Tue Apr 10, 2012 6:39 pm; edited 2 times in total
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Subject Author Date/Time
YBWC: Active Reparenting Marco Costalba Tue Apr 10, 2012 5:38 pm
      Re: YBWC: Active Reparenting Vincent Diepeveen Tue Apr 10, 2012 6:23 pm
            Re: YBWC: Active Reparenting Daniel Shawul Tue Apr 10, 2012 7:11 pm
                  Re: YBWC: Active Reparenting Vincent Diepeveen Tue Apr 10, 2012 7:54 pm
                        Re: YBWC: Active Reparenting Marco Costalba Tue Apr 10, 2012 8:48 pm
                              Re: YBWC: Active Reparenting Vincent Diepeveen Wed Apr 11, 2012 10:09 am
                                    Re: YBWC: Active Reparenting Robert Hyatt Mon Apr 16, 2012 6:53 pm
                        Re: YBWC: Active Reparenting Daniel Shawul Tue Apr 10, 2012 11:11 pm
                              Re: YBWC: Active Reparenting Daniel Shawul Tue Apr 10, 2012 11:33 pm
                              Re: YBWC: Active Reparenting Robert Hyatt Mon Apr 16, 2012 7:07 pm
                                    Re: YBWC: Active Reparenting Vincent Diepeveen Mon Apr 16, 2012 8:55 pm
                                          Re: YBWC: Active Reparenting Robert Hyatt Tue Apr 17, 2012 2:54 pm
                                                Re: YBWC: Active Reparenting Daniel Shawul Tue Apr 17, 2012 5:42 pm
                                                      Re: YBWC: Active Reparenting Robert Hyatt Tue Apr 17, 2012 8:01 pm
                                                            Re: YBWC: Active Reparenting Daniel Shawul Tue Apr 17, 2012 9:34 pm
                                                                  Re: YBWC: Active Reparenting Robert Hyatt Tue Apr 17, 2012 9:46 pm
                                                                        Re: YBWC: Active Reparenting Daniel Shawul Tue Apr 17, 2012 10:30 pm
                                                                              Re: YBWC: Active Reparenting Vincent Diepeveen Tue Apr 17, 2012 11:43 pm
                                                                                    Re: YBWC: Active Reparenting Daniel Shawul Wed Apr 18, 2012 1:05 am
                                                                                          Re: YBWC: Active Reparenting Vincent Diepeveen Wed Apr 18, 2012 11:24 am
                                                                                          Re: YBWC: Active Reparenting Daniel Shawul Wed Apr 18, 2012 1:01 pm
                                                                              Re: YBWC: Active Reparenting Robert Hyatt Wed Apr 18, 2012 7:34 pm
                                                                                    Re: YBWC: Active Reparenting Daniel Shawul Wed Apr 18, 2012 11:18 pm
                                                                                          Re: YBWC: Active Reparenting Vincent Diepeveen Thu Apr 19, 2012 7:01 am
                                                                                          Re: YBWC: Active Reparenting Daniel Shawul Thu Apr 19, 2012 12:46 pm
                                                                                          Re: YBWC: Active Reparenting Vincent Diepeveen Thu Apr 19, 2012 2:40 pm
                                                                                          Re: YBWC: Active Reparenting Daniel Shawul Thu Apr 19, 2012 9:32 pm
                                                                                          Re: YBWC: Active Reparenting Robert Hyatt Thu Apr 19, 2012 7:08 pm
                                                                                          Re: YBWC: Active Reparenting Daniel Shawul Thu Apr 19, 2012 9:37 pm
                                                                                          Re: YBWC: Active Reparenting Robert Hyatt Thu Apr 19, 2012 9:48 pm
                                                                                          Re: YBWC: Active Reparenting Robert Hyatt Thu Apr 19, 2012 6:59 pm
                                                                                          Re: YBWC: Active Reparenting Robert Hyatt Thu Apr 19, 2012 5:30 pm
                                                                        Re: YBWC: Active Reparenting Vincent Diepeveen Tue Apr 17, 2012 11:29 pm
                                                                              Re: YBWC: Active Reparenting Daniel Shawul Wed Apr 18, 2012 12:58 am
                                                                  Re: YBWC: Active Reparenting Vincent Diepeveen Tue Apr 17, 2012 11:18 pm
                                    Re: YBWC: Active Reparenting Daniel Shawul Tue Apr 17, 2012 5:37 pm
      Re: YBWC: Active Reparenting Álvaro Begué Tue Apr 10, 2012 6:27 pm
            Re: YBWC: Active Reparenting Vincent Diepeveen Tue Apr 10, 2012 6:44 pm
      Re: YBWC: Active Reparenting Robert Hyatt Tue Apr 10, 2012 9:39 pm
            Re: YBWC: Active Reparenting Marco Costalba Wed Apr 11, 2012 6:06 am
                  Re: YBWC: Active Reparenting Robert Hyatt Thu Apr 12, 2012 1:20 am
                        Re: YBWC: Active Reparenting Vincent Diepeveen Sun Apr 15, 2012 10:04 am
                              Re: YBWC: Active Reparenting Marco Costalba Sun Apr 15, 2012 10:22 am
                                    Re: YBWC: Active Reparenting Vincent Diepeveen Sun Apr 15, 2012 2:39 pm
                                          Re: YBWC: Active Reparenting Marco Costalba Mon Apr 16, 2012 5:29 am
                                                Re: YBWC: Active Reparenting Vincent Diepeveen Mon Apr 16, 2012 5:54 pm
                                                      Re: YBWC: Active Reparenting Marco Costalba Tue Apr 17, 2012 11:30 am
                                                Re: YBWC: Active Reparenting Marco Costalba Wed Apr 18, 2012 6:31 am
      Re: YBWC: Active Reparenting Rein Halbersma Wed Apr 11, 2012 7:23 am
            Re: YBWC: Active Reparenting Vincent Diepeveen Wed Apr 11, 2012 9:07 am
            Re: YBWC: Active Reparenting Vincent Diepeveen Wed Apr 11, 2012 9:31 am
            Re: YBWC: Active Reparenting Daniel Shawul Wed Apr 11, 2012 12:14 pm
                  Re: YBWC: Active Reparenting Vincent Diepeveen Wed Apr 11, 2012 1:54 pm
                  Re: YBWC: Active Reparenting Robert Hyatt Thu Apr 12, 2012 1:28 am
                        Re: YBWC: Active Reparenting Daniel Shawul Tue Apr 17, 2012 5:49 pm
                              Re: YBWC: Active Reparenting Vincent Diepeveen Tue Apr 17, 2012 11:10 pm
                                    Re: YBWC: Active Reparenting Daniel Shawul Wed Apr 18, 2012 12:50 am
                              Re: YBWC: Active Reparenting Robert Hyatt Wed Apr 18, 2012 7:38 pm
                                    Re: YBWC: Active Reparenting Daniel Shawul Wed Apr 18, 2012 11:30 pm
                                          Re: YBWC: Active Reparenting Vincent Diepeveen Thu Apr 19, 2012 7:08 am
                                                Re: YBWC: Active Reparenting Daniel Shawul Thu Apr 19, 2012 12:15 pm
                                                      Re: YBWC: Active Reparenting Vincent Diepeveen Thu Apr 19, 2012 1:53 pm
                                          Re: YBWC: Active Reparenting Robert Hyatt Thu Apr 19, 2012 7:11 pm
      Re: GPUs Srdja Matovic Mon Jun 04, 2012 5:08 pm
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