Messages in this thread | | | Date | Wed, 04 Jun 2008 10:47:58 -0700 | From | Max Krasnyansky <> | Subject | Re: Inquiry: Should we remove "isolcpus= kernel boot option? (may have realtime uses) |
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Ingo Oeser wrote: > Hi Max, > > On Wednesday 04 June 2008, Max Krasnyanskiy wrote: >> btw Ingo, I just realized that maxcpu= option is exactly what you need. >> Here is how you can use it. >> Boot your system with maxcpus=1. That way the kernel will only bring up >> processor 0. I'm assuming cpu0 is "good" otherwise your system is totally >> busted :). Other cpus will stay off-line and will not be initialized. >> Then once the system boots you can selectively bring "good" processors online >> by doing >> echo 1 > /sys/devices/system/cpu/cpuN/online >> > > I just tested it on the Ubuntu Hardy standard kernel on an AMD DualCore. > The /sys/devices/system/cpu/cpu1 entry doesn't show up. > > I can send you the dmesg/config in private, if you want. > > Did you test your suggestion? No, I just give random suggestions without verifying them first ;-). Of course I tried it. Sounds like your Ubuntu kernel does not have "CPU hotplug / suspend on SMP" enabled. I thought that all distributions enable it by default these days.
Max
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