• Huang Rui's avatar
    perf/x86/amd/power: Add AMD accumulated power reporting mechanism · c7ab62bf
    Huang Rui authored
    Introduce an AMD accumlated power reporting mechanism for the Family
    15h, Model 60h processor that can be used to calculate the average
    power consumed by a processor during a measurement interval. The
    feature support is indicated by CPUID Fn8000_0007_EDX[12].
    
    This feature will be implemented both in hwmon and perf. The current
    design provides one event to report per package/processor power
    consumption by counting each compute unit power value.
    
    Here the gory details of how the computation is done:
    
    * Tsample: compute unit power accumulator sample period
    * Tref: the PTSC counter period (PTSC: performance timestamp counter)
    * N: the ratio of compute unit power accumulator sample period to the
      PTSC period
    
    * Jmax: max compute unit accumulated power which is indicated by
      MSR_C001007b[MaxCpuSwPwrAcc]
    
    * Jx/Jy: compute unit accumulated power which is indicated by
      MSR_C001007a[CpuSwPwrAcc]
    
    * Tx/Ty: the value of performance timestamp counter which is indicated
      by CU_PTSC MSR_C0010280[PTSC]
    * PwrCPUave: CPU average power
    
    i. Determine the ratio of Tsample to Tref by executing CPUID Fn8000_0007.
    	N = value of CPUID Fn8000_0007_ECX[CpuPwrSampleTimeRatio[15:0]].
    
    ii. Read the full range of the cumulative energy value from the new
        MSR MaxCpuSwPwrAcc.
    	Jmax = value returned.
    
    iii. At time x, software reads CpuSwPwrAcc and samples the PTSC.
    	Jx = value read from CpuSwPwrAcc and Tx = value read from PTSC.
    
    iv. At time y, software reads CpuSwPwrAcc and samples the PTSC.
    	Jy = value read from CpuSwPwrAcc and Ty = value read from PTSC.
    
    v. Calculate the average power consumption for a compute unit over
    time period (y-x). Unit of result is uWatt:
    
    	if (Jy < Jx) // Rollover has occurred
    		Jdelta = (Jy + Jmax) - Jx
    	else
    		Jdelta = Jy - Jx
    	PwrCPUave = N * Jdelta * 1000 / (Ty - Tx)
    
    Simple example:
    
      root@hr-zp:/home/ray/tip# ./tools/perf/perf stat -a -e 'power/power-pkg/' make -j4
        CHK     include/config/kernel.release
        CHK     include/generated/uapi/linux/version.h
        CHK     include/generated/utsrelease.h
        CHK     include/generated/timeconst.h
        CHK     include/generated/bounds.h
        CHK     include/generated/asm-offsets.h
        CALL    scripts/checksyscalls.sh
        CHK     include/generated/compile.h
        SKIPPED include/generated/compile.h
        Building modules, stage 2.
      Kernel: arch/x86/boot/bzImage is ready  (#40)
        MODPOST 4225 modules
    
       Performance counter stats for 'system wide':
    
                  183.44 mWatts power/power-pkg/
    
           341.837270111 seconds time elapsed
    
      root@hr-zp:/home/ray/tip# ./tools/perf/perf stat -a -e 'power/power-pkg/' sleep 10
    
       Performance counter stats for 'system wide':
    
                    0.18 mWatts power/power-pkg/
    
            10.012551815 seconds time elapsed
    Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
    Suggested-by: default avatarIngo Molnar <mingo@kernel.org>
    Suggested-by: default avatarBorislav Petkov <bp@suse.de>
    Signed-off-by: default avatarHuang Rui <ray.huang@amd.com>
    Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
    Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: David Ahern <dsahern@gmail.com>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Kan Liang <kan.liang@intel.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Robert Richter <rric@kernel.org>
    Cc: Stephane Eranian <eranian@google.com>
    Cc: Vince Weaver <vincent.weaver@maine.edu>
    Cc: jacob.w.shin@gmail.com
    Link: http://lkml.kernel.org/r/1457502306-2559-1-git-send-email-ray.huang@amd.com
    [ Fixed the modular build. ]
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
    c7ab62bf
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