Messages in this thread | | | Subject | Re: [PATCH 1/2] include: trace: Add SCMI header with trace events | From | Jim Quinlan <> | Date | Fri, 20 Dec 2019 11:24:03 -0500 |
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> Thank you for sharing your experiments and thoughts. I have probably > similar setup for stressing the communication channel, but I do also > some wired things in the firmware. That's why I need to measure these > delays. I am happy that it is useful for you also. > > I don't know if your firmware supports 'fast channel', but please keep > in mind that it is not tracked in this 'transfer_id'. > This transfer_id in v2 version does not show the real transfers > to the firmware since there is another path called 'fast channel' or > 'fast_switch' in the CPUfreq. It is in drivers/firmware/arm_scmi/perf.c > and the atomic variable is not incremented in that path. Adding it also > there just for atomic_inc() probably would add delays in the fast_switch > and also brings little value. > For the normal channel, where we have spinlocks and other stuff, this > atomic_inc() could stay in my opinion. > > Regards, > Lukasz Hi Lukasz,
We currently do not use "fast channels" - although it is possible we might someday. I find the transfer_id useful per your v2 even if it doesn't cover FC. Thanks for submitting and discussing this!
Regards, Jim Quinlan
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