Messages in this thread | | | Subject | Re: [PATCH] powerpc/powernv: Add kernel cmdline parameter to disable imc | From | Anju T Sudhakar <> | Date | Wed, 11 Oct 2017 14:26:27 +0530 |
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Hi mpe, stewart,
On Wednesday 11 October 2017 01:55 AM, Stewart Smith wrote: > Michael Ellerman <mpe@ellerman.id.au> writes: >> Anju T Sudhakar <anju@linux.vnet.ibm.com> writes: >> >>> Add a kernel command line parameter option to disable In-Memory Collection >>> (IMC) counters and add documentation. This helps in debug. >> I'd really rather we didn't. Do we *really* need this? >> >> We don't have command line parameters to disable any of the other ~20 >> PMUs, why is this one special?
This one is really helpful in debugging, incase if we want to proceed without nest counters OR core counters . But if we have the facility to do the same from petitboot, its fine.
> You could also do the same thing by editing the device tree before > booting your kernel, we do have the facility to do that in petitboot. > > A recent firmware patch: https://patchwork.ozlabs.org/patch/823249/ > would fix the firmware implementation where the counters were already > running before the INIT/START calls, which are likely the cause of the > problems that this patch is trying to work around. > > I propose we have the firmware do the right thing and nothing special in > kernel. i.e. not to merge this. >
Agreed.
Thanks, Anju
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