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1.1 |
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13-Jul-2018 |
maxv |
Revamp tprof.
Rewrite the Intel backend to use the generic PMC interface, which is
available on all Intel CPUs. Synchronize the AMD backend with the new
interface.
The kernel identifies the PMC interface, and gives its id to userland.
Userland then queries the events itself (via cpuid etc). These events
depend on the PMC interface.
The tprof utility is rewritten to allow the user to choose which event
to count (which was not possible until now, the event was hardcoded in
the backend). The command line format is based on usr.bin/pmc, eg:
tprof -e llc-misses:k -o output sleep 20
The man page is updated too, but the arguments will likely change soon
anyway so it doesn't matter a lot.
The tprof utility has three tables:
Intel Architectural Version 1
Intel Skylake/Kabylake
AMD Family 10h
A CPU can support a combination of tables. For example Kabylake has
Intel-Architectural-Version-1 and its own Intel-Kabylake table.
For now the Intel Skylake/Kabylake table contains only one event, just
to demonstrate that the combination of tables works. Tested on an
Intel Core i5 Kabylake.
The code for AMD Family 10h is taken from the code I had written for
usr.bin/pmc. I haven't tested it yet, but it's the same as pmc(1), so
I guess it works as-is.
The whole thing is written in such a way that (I think) it is not
complicated to add more CPU models, and more architectures (other than
x86).
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