![]() This information is also available via the sysctl set of system calls, and, in particular the sysctlbyname call. Here we’re asking for hardware and machine information:- $ sysctl -a hw machdep.cpu compiler: appleclang: (only on macOS) its corresponding value is a list of maps whose values contain the information of the Apple Clang compiler that is on /. What we do have on MacOS is the sysctl command, which will show us similar information (though in a less compact form). However, lscpu is not supported on MacOS (at least not to the depth of my Google-fu) that is hardly surprising, since it is effectively a summary of /proc/cpuinfo which is a Linux invention. Model name: Intel(R) Xeon(R) CPU E5-2695 v4 2.10GHzįlags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch epb cat_l3 cdp_l3 invpcid_single intel_ppin intel_pt tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm cqm rdt_a rdseed adx smap xsaveopt cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts For instance, on the Isambard 1 login node, we see this :-bash-4.2$ lscpu Which suffices for most programs.If you are used to Linux, you probably expect to be able to find out a lot about your machine by looking in /proc/cpuinfo, or using lscpu. It uses 'lxcfs' to bind mount onto /proc/cpuinfo and modifies the output to only show the number of CPU cores you actually have. It would be nice to advance the scheduler to support such a concept without using the quotas specifically.Īs a final side note. You have to reduce the CPU set down to 4 specific CPUs and now if all containers scheduled to those specific 4 CPUs are busy you will be losing time to those other containers when a different 4 CPUs may be totally idle. You may then ask why not reduce the CPU set for those containers, the problem is there is no way (at least currently) to say 'this process can only run on 4 CPUs, but any of them'. macOS Big Sur Developer Preview not being detected as Mac OS X. However the problem comes if you have 12 threads consuming your 4 threads worth of CPU time they'll end up block for 5-10 or more milliseconds at a time where they may well be holding that lock and preventing the other threads from running. which is precisely what happens with multi threaded Python programs (they sometimes contend on the GIL) that use data science modules which do a lot of processing in C without the GIL lock held and only take it occasionally. ![]() If you want to understand more about these problems this article has some good background, although they fixed a real bug in the scheduler here the background will give you the general idea and it's still a problem to some extent if all of those threads/processes are trying to contend on a single shared lock. ![]() It would be ideal to have a standard utility or library that would also check that. you may have 12 active cores but only a budget of 4 CPUs worth of CPU time. nproc specifically does not currently check your CFS CPU cgroup quota, i.e. This is 100% a problem I was working on for a customer recently.
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