On Tue, Jul 19, 2016 at 10:22:39AM +0200, R??my Dernat wrote: > Hi, > I have many nodes with hyperthreading enable. > I would like to know if modifying the complex value 'num_proc' or 'slots' > to the half of cores is the same thing that to disable the hyperthreading. > If not, what is the difference ? > Thanks, > Best regards, > Remy Slots controls how many jobs or pe_tasks grid engine will launch on the node. With CPU binding this will control how many virtual CPUs are used but doesn't directly control which virtual CPUs will be used. If a user requested linear binding of their job they would get adjacent cores meaning multiple threads on the same core.
If you want to stop more than one thread from the same core being used and you are using linux you can disable a virtual cpu by echoing 0 into /sys/devices/system/cpu/cpu<number>/online. If you do that for the second virtual cpu on each core you should achieve a similar effect to disabling hyperthreading. You'll probably want to restart the sge_execd after doing this so it isn't too confused about what cores are available but this method is a bit less hassle and more portable across different makes of hardware then poking around in the BIOS(poking around in the UEFI?). William
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