Re: erlang:system_info(cpu_topology) strange behavior
Rickard Green <[email protected]>
| Newsgroups | gmane.comp.lang.erlang.general |
|---|---|
| Message-ID | <CAA_Z33M-wgyHuk5gNw9t2Yc+nbQudJnakCOjjNkV6pYPcei_uA@mail.gmail.com> |
On Thu, Oct 8, 2020 at 7:36 PM Frank Muller <[email protected]> wrote: > Answering my own question. > > The second attempt worked because I was under “root”. > > Attaching to the release with -remsh failed because the node was running > under user “orca” which has less privileges. > > Is this an expected behavior? > > /Frank > > The runtime system gets the information about cpu topology by reading files under /sys/devices/system/. If it cannot read and parse the files there, it will fail to detect the cpu topology. Seems like only root is allowed to read that part of the file-system in your case. Regards, Rickard Green > Frank<[email protected]> > >> Hi guys, >> >> When I attached (-remsh) to my release application (/opt/orca), this call >> returns undefined: >> >> ([email protected])1> erlang:system_info(cpu_topology). >> undefined >> >> If try this instead, the call seems to work as expected: >> >> $ /opt/orca/erts-10.7.2.4/bin/erl >> 1> erlang:system_info(cpu_topology). >> [{processor,[{core,[{thread,{logical,0}}, >> {thread,{logical,4}}]}, >> {core,[{thread,{logical,1}},{thread,{logical,5}}]}, >> {core,[{thread,{logical,2}},{thread,{logical,6}}]}, >> {core,[{thread,{logical,3}},{thread,{logical,7}}]}]}] >> >> >> I’m on Ubuntu16 LTS kernel 4.4.0, Erlang 22.3.4.11. >> >> Help appreciated >> >> /Frank >> > -- Rickard Green, Erlang/OTP, Ericsson AB