On 2023-09-07 at 16:19:37 +0000, Luck, Tony wrote: >> > + if (4 * node_cpus >= cache_cpus) >> > + return 4; >> > + else if (2 * node_cpus >= cache_cpus) >> > + return 2; >> >> >> If "4 * node_cpus >= cache_cpus " is not true， >> "2 * node_cpus >= cache_cpus" will never be true. >> Is it the following code? >> >> + if (2 * node_cpus >= cache_cpus) >> + return 2; >> + else if (4 * node_cpus >= cache_cpus) >> + return 4; > > >Shaopeng TAN, > >Good catch. Your solution is the correct one. > >Will fix in next post. I played around with this code a little and I think the logical expressions are returning wrong values. On a system that has SNC disabled the function reports both "node_cpus" and "cache_cpus" equal to 56. In this case snc_ways() returns "2". It is the same on a system with SNC enabled that reports the previously mentioned variables to be different by a factor of two (36 and 72). Is it possible for node_cpus and cache_cpus to not be multiples of each other? (as in for example cache_cpus being 10 and node_cpus being 21?). If not I'd suggest using "==" instead of ">=". If yes then I guess something like this could work? : + if (node_cpus >= cache_cpus) + return 1; + else if (2 * node_cpus >= cache_cpus) + return 2; + else if (4 * node_cpus >= cache_cpus) + return 4; PS. I did my tests on two Intel Ice Lakes. -- Kind regards Maciej Wieczór-Retman
