Integer overflow when memory limit is less than NN cache memory usage

[mooskagh]

Example with memory limit 1MB:

0630 18:21:32.324037 36208 c:\projects\lc0\src\mcts\stoppers\stoppers.cc:110] RAM limit 1MB. Cache takes 59MB. Remaining memory is enough for 92233720368256758 nodes.

[ErdoganSeref]

Does the integer overflow occur regarding the number of available nodes? How can we reproduce the issue?

[mooskagh]

I believe if you run ./lc0 with --ramlimit-mb=1 "--logfile=<stderr>", the issue will show up.
(instead of <stderr>, you can write log to a logfile, --logfile=filename.txt)

[ErdoganSeref]

When I run ./lc0 --ramlimit-mb=1 "--logfile=log.txt" I get the following log:

0516 17:20:23.509182 140325955516224 ../../src/main.cc:45] Lc0 started. 0516 17:20:23.509351 140325955516224 ../../src/main.cc:46] _ 0516 17:20:23.509421 140325955516224 ../../src/main.cc:47] | _ | | 0516 17:20:23.509476 140325955516224 ../../src/main.cc:48] |_ |_ |_| v0.30.0-dev+git.dirty built May 10 2022 0516 17:20:23.525305 140325955516224 ../../src/utils/commandline.cc:56] Command line: ./lc0 --ramlimit-mb=1 --logfile=log.txt

I can't see the issue in the log file.

[mooskagh]

Run some actual search, with go wtime 1000 or something like that.

[ErdoganSeref]

I reproduced the issue by running ./lc0 --ramlimit-mb=1 "--logfile=log.txt" followed by go wtime 1000 as you've said. But I still don't understand what the exact issue is. What should the expected output be?

[mooskagh]

When "negative" amount of RAM is available (cache use is larger than total avaialable), it should allocate 0 nodes and not 92233720368256758.

[Naphthalin]

Was this addressed lately when RAM limit was discussed?

[KarlKfoury]

i believe #2058 fixes issue