clr_cpufreq.py

#!/usr/bin/env python3
#
# coolr cpufreq related codes
#
# There is no perfect way to read the CPU clock on x86.  We need to
# read TSC, APERF and MPERF to estimate the current cpu clock on x86.
#
# This code requires the cpustat driver
#
# Contact: Kazutomo Yoshii <ky@anl.gov>
#

import os, sys, time
import struct
import copy
import clr_nodeinfo
import numpy as np

#an example the content of cpustat
#id                    0
#aperf     4926926121023
#mperf     4582847073452
#perf_bias             8
#ucc     281462841145699
#urc                   0
#perf_target        8448
#perf_status        8448
#pstate               33
#turbo_disengage       0
#tsc    1117245755950154

class cpustatvals:
    def cpustatfn(self, cpuid):
        return "/sys/devices/system/cpu/cpu%d/cpustat/cpustat" % cpuid

    def __init__(self, cpuid):
        self.u64max = (1 << 64) - 1
        self.d = {}
        self.cpuid = cpuid

    def parse(self):
        self.d = {} # clear d's contents
        self.d['time'] = time.time()
        with open(self.cpustatfn(self.cpuid)) as f:
            while True:
                l = f.readline()
                if not l:
                    break
                a = l.split()
                if a[0] in ('id', 'aperf', 'mperf', 'pstate', 'tsc'):
                    self.d[a[0]] = int(a[1])

    def pr(self):
        for k in ('id', 'aperf', 'mperf', 'pstate', 'tsc'):
            print('%s=%d ' % (k, self.d[k]), end=' ')
        print()

    def diff_u64(self, v1, v2): # v1 - v2
        if v1 >= v2:
            return v1 - v2
        return (self.u64max -v2) + v1

    def calc_cpufreq(self,prev): # prev is an object of cpustatvals
        if not ('tsc' in prev.d and 'tsc' in self.d):
                    return 0.0
        tmp = {}
        for k in ('tsc', 'aperf', 'mperf'):
            tmp[k] = float(self.diff_u64(self.d[k], prev.d[k]))

        dt = self.d['time'] - prev.d['time']
        freq = tmp['aperf'] / tmp['mperf']
        freq *= tmp['tsc']
        freq *= 1e-9  # covert it to GHz
        freq /= dt

        return freq


    def calc_aperf(self,prev): # prev is an object of cpustatvals
        if not ('tsc' in prev.d and 'tsc' in self.d):
                    return 0.0
        tmp = {}
        k = 'aperf'
        tmp[k] = float(self.diff_u64(self.d[k], prev.d[k]))

        dt = self.d['time'] - prev.d['time']
        return tmp['aperf'] * 1e-9 / dt


class cpufreq_reader:

    def __init__(self):
        self.outputpercore(True)

        # I don't know how to create an object in a singleton manner in python
        # so simply instantiating an object of cputopology again here.
        self.ct = clr_nodeinfo.cputopology()

        self.cpus = self.ct.onlinecpus # just for convenience

        self.init = False

        for cpuid in self.cpus:
            tmp = cpustatvals(cpuid) # just for cpustatfn
            statpath = tmp.cpustatfn(cpuid)
            if not os.path.exists(statpath):
                # print 'Not found', statpath
                return

        self.init = True
        self.cnt = 0
        self.samples = [
            [cpustatvals(i) for i in self.cpus],
            [cpustatvals(i) for i in self.cpus] ]

        self.sample()

    def sample(self):
        if not self.init:
            return

        idx = self.cnt % 2
        for cpuid in self.cpus:
            self.samples[idx][cpuid].parse()
        self.cnt = self.cnt + 1


    def pstate(self):
        ret = [0.0 for i in self.cpus]
        if not self.init:
            return ret
        if self.cnt == 0:
            return ret

        idx = 0 # if cnt is an odd number
        if self.cnt % 2 == 0:
            idx = 1
        for cpuid in self.cpus:
            ret[cpuid] = self.samples[idx][cpuid].d['pstate']

        return ret

    def cpufreq(self):
        ret = [0.0 for i in self.cpus]
        if not self.init:
            return ret
        if self.cnt < 2:
            return ret

        idxprev = 0
        idxcur = 1
        if (self.cnt % 2) == 1:
            idxprev = 1
            idxcur = 0

        for cpuid in self.cpus:
            ret[cpuid] = self.samples[idxcur][cpuid].calc_cpufreq(
                self.samples[idxprev][cpuid])

        return ret

    def aperf(self):
        ret = [0.0 for i in self.cpus]
        if not self.init:
            return ret
        if self.cnt < 2:
            return ret

        idxprev = 0
        idxcur = 1
        if (self.cnt % 2) == 1:
            idxprev = 1
            idxcur = 0

        for cpuid in self.cpus:
            ret[cpuid] = self.samples[idxcur][cpuid].calc_aperf(
                self.samples[idxprev][cpuid])

        return ret

    def outputpercore(self,flag=True):
        self.percore=flag

    def sample_and_json(self, node=""):
        if not self.init:
            return ''

        self.sample()
        f = self.aperf()

        buf = '{"sample":"freq", "time":%.3f' % time.time()
        if len(node) > 0:
            buf += ',"node":"%s"' % node
        for p in sorted(self.ct.pkgcpus.keys()):
            tmp = [f[i] for i in self.ct.pkgcpus[p]]
            freqmean = np.mean(tmp)
            freqstd = np.std(tmp)

            buf += ',"p%s":{' % p
            buf += '"mean":%.3lf,"std":%.3lf' % (freqmean,freqstd)
            if self.percore:
                for c in self.ct.pkgcpus[p]:
                    buf += ',"c%d":%.3lf' % (c, f[c])
            buf += '}'
        buf += '}'
        return buf



if __name__ == '__main__':

    freq = cpufreq_reader()
    if not freq.init:
        print('Please check the cpustat module is installed')
        sys.exit(1)

    freq.outputpercore(False)

    for i in range(0, 20):
        j = freq.sample_and_json()
        print('[freq json]')
        print(j)
        time.sleep(1)

    sys.exit(0)

    for i in range(0, 20):
        freq.sample()

        print('[pstate]', end=' ')
        for p in freq.pstate():
            print(p, end=' ')
        print()

        print('[aperf]', end=' ')
        for f in freq.aperf():
            print('%.2lf ' % f, end=' ')
        print()

        print('[freq]', end=' ')
        for f in freq.cpufreq():
            print('%.2lf ' % f, end=' ')
        print()

        j = freq.sample_and_json()
        print('[freq json]')
        print(j)

        print()
        time.sleep(1)