Page 1 of 2

Syzygy 7 piece Machine slow down

Posted: Wed Aug 28, 2019 7:51 pm
by first25plus5
Hi my computer system basics are as follows: Windows 10 Pro, 3.1Ghz, 16BG RAM, 64bit-Quad core. I have the more important 7piece Table bases downloaded onto a SSD SATA drive totalling 443GB and more on another drive totalling 219GB. While I'm running Stockfish10 it isn't very long before (going by task manager) the CPU almost suddenly grinds to a virtual halt and also the C-drive usage increases dramatically. I have varied the hashtable settings and the Virtual Memory in the system, as there is enough space on the SSD drives to be inside the computer system's own recommendations on virtual memory settings. I suspect perhaps the 7-piece syzygy files are so big that I need tons more RAM. Does anyone have any suggestions please. Thanks in advance.

Re: Syzygy 7 piece Machine slow down

Posted: Wed Aug 28, 2019 7:53 pm
by first25plus5
Forgot to mention that I have this issue in both Arena and Chessbase, so suspect it's a memory allocation issue.

Re: Syzygy 7 piece Machine slow down

Posted: Wed Aug 28, 2019 8:08 pm
by Sesse
More RAM would help, and most likely, your SSD is also pretty slow. Failing that, you can ask to probe less often (increase SyzygyProbeDepth).

Re: Syzygy 7 piece Machine slow down

Posted: Wed Aug 28, 2019 8:08 pm
by Dann Corbit
16 GB RAM is really small.
I guess that you are getting page faults.

Re: Syzygy 7 piece Machine slow down

Posted: Thu Aug 29, 2019 7:52 pm
by first25plus5
Hi all thankyou very much. Yes it does appear that the main issue is far too little RAM. I've learnt a few things. Many thanks for all the help. Regards.

Re: Syzygy 7 piece Machine slow down

Posted: Thu Aug 29, 2019 8:06 pm
by Modern Times
Yes, with 16GB RAM even with 6-men my machine would start paging on long analysis. I restrict myself to 5-men now.

Re: Syzygy 7 piece Machine slow down

Posted: Fri Aug 30, 2019 12:08 pm
by syzygy
first25plus5 wrote:
Thu Aug 29, 2019 7:52 pm
Hi all thankyou very much. Yes it does appear that the main issue is far too little RAM. I've learnt a few things. Many thanks for all the help. Regards.
In addition to increasing SyzygyProbeDepth, you could try disabling the Windows pagefile (which I suppose is on the non-SSD C drive).

Most likely it will still be slow but it should stop the C-drive usage.

Moving the pagefile to the SSD would NOT be a good idea in this situation, since extreme paging is not healthy for an SSD.

I think 16GB RAM is really the lower limit for using 6-piece TBs. For 7-piece TBs, think 1TB RAM.

Re: Syzygy 7 piece Machine slow down

Posted: Wed Sep 04, 2019 10:14 pm
by first25plus5
Many thanks. Yes I totally agree with 16GB RAM as a lower limit for 6-piece tb. (15.8GB free on my system of the 16GB)
I was even having issues with 6-piece tb prior to this.
My solution for 6-piece on my machine is to set my HASH to 9 GB, and the cache setting to 1 GB. (Leaves 8GB of the 9GB HASH for the machine to work well.) Runs beautifully, and I still get a great amount of 6-pieces on my SSD stick, which I discovered I should not fill past about 15 GB to 16 GB. I have topped my SSD stick up to reach 14.9 GB as it has turned out. Anything much past that and it causes issues. Perhaps something to do with the RAM free reading the SSD drive.

Getting back to 7-piece tb, perhaps the tb files should be no larger than the amount of RAM free on a machine.
E.g. if there are 500 GB of tb files, then RAM be a little more, say 512 GB.
Cheers

Re: Syzygy 7 piece Machine slow down

Posted: Thu Sep 05, 2019 7:44 am
by syzygy
first25plus5 wrote:
Wed Sep 04, 2019 10:14 pm
I was even having issues with 6-piece tb prior to this.
My solution for 6-piece on my machine is to set my HASH to 9 GB, and the cache setting to 1 GB. (Leaves 8GB of the 9GB HASH for the machine to work well.)
I'm not sure what you mean by "cache setting". If this is about the Nalimov cache (don't know what engine you're using), then it does not influence Syzygy behaviour.
Runs beautifully, and I still get a great amount of 6-pieces on my SSD stick, which I discovered I should not fill past about 15 GB to 16 GB. I have topped my SSD stick up to reach 14.9 GB as it has turned out. Anything much past that and it causes issues. Perhaps something to do with the RAM free reading the SSD drive.
If you want to get rid of the swapping, disable the Windows pagefile. It may not be the ideal solution, but it works.
Getting back to 7-piece tb, perhaps the tb files should be no larger than the amount of RAM free on a machine.
E.g. if there are 500 GB of tb files, then RAM be a little more, say 512 GB.
No, it should work fine with bigger files if Windows would just not swap out active programs to the pagefile and instead release TB data from the system cache. The easiest way to achieve this is to disable the pagefile, so Windows can't swap out active programs in the first place.

Re: Syzygy 7 piece Machine slow down

Posted: Sun Sep 08, 2019 7:49 pm
by first25plus5
Thanks again and for your patience. I'm using Stockfish and have removed the cache setting. I tried disabling the windows paging file but the computer has problem starting up.
So I have had to leave the windows paging file back on and have increased the HASH to 14GB and re-tested.
Seems fine, but can't go larger with the total size of the tb files which remain at 14.9 GB.