# SPDX-License-Identifier: GPL-2.0-or-later
#
#   cyclictest.py - object to manage a cyclictest executable instance
#
#   Copyright 2009 - 2013   Clark Williams <williams@redhat.com>
#   Copyright 2012 - 2013   David Sommerseth <davids@redhat.com>
#
""" cyclictest.py - object to manage a cyclictest executable instance """

import os
import subprocess
import signal
import time
import tempfile
import math
import libxml2
from rteval.Log import Log
from rteval.modules import rtevalModulePrototype
from rteval.systopology import cpuinfo, SysTopology
from rteval.cpulist_utils import expand_cpulist, collapse_cpulist

class RunData:
    '''class to keep instance data from a cyclictest run'''
    def __init__(self, coreid, datatype, priority, logfnc):
        self.__id = coreid
        self.__type = datatype
        self.__priority = int(priority)
        self.description = ''
        # histogram of data
        self.__samples = {}
        self.__numsamples = 0
        self.__min = 100000000
        self.__max = 0
        self.__stddev = 0.0
        self.__mean = 0.0
        self.__mode = 0.0
        self.__median = 0.0
        self.__range = 0.0
        self.__mad = 0.0
        self._log = logfnc

    def __str__(self):
        retval = f"id:         {self.__id}\n"
        retval += f"type:       {self.__type}\n"
        retval += f"numsamples: {self.__numsamples}\n"
        retval += f"min:        {self.__min}\n"
        retval += f"max:        {self.__max}\n"
        retval += f"stddev:     {self.__stddev}\n"
        retval += f"mad:        {self.__mad}\n"
        retval += f"mean:       {self.__mean}\n"
        return retval

    def get_max(self):
        return self.__max

    def update_max(self, value):
        if value > self.__max:
            self.__max = value

    def update_min(self, value):
        if value < self.__min:
            self.__min = value

    def bucket(self, index, value):
        self.__samples[index] = self.__samples.setdefault(index, 0) + value
        if value:
            self.update_max(index)
            self.update_min(index)
        self.__numsamples += value

    def reduce(self):

        # check to see if we have any samples and if we
        # only have 1 (or none) set the calculated values
        # to zero and return
        if self.__numsamples <= 1:
            self._log(Log.DEBUG, f"skipping {self.__id} ({self.__numsamples} samples)")
            self.__mad = 0
            self.__stddev = 0
            return

        self._log(Log.INFO, f"reducing {self.__id}")
        total = 0 # total number of samples
        total_us = 0
        keys = list(self.__samples.keys())
        keys.sort()

        # if numsamples is odd, then + 1 gives us the actual mid
        # if numsamples is even, we avg mid and mid + 1, so we actually
        # want to know mid + 1 since we will combine it with mid and
        # the lastkey if the last key is at the end of a previous bucket
        mid = int(self.__numsamples / 2) + 1

        # mean, mode, and median
        occurrences = 0
        lastkey = -1
        for i in keys:
            if mid > total and mid <= total + self.__samples[i]:
                # Test if numsamples is even and if mid+1 is the next bucket
                if self.__numsamples & 1 != 0 and mid == total+1:
                    self.__median = (lastkey + i) / 2
                else:
                    self.__median = i
            lastkey = i
            total += self.__samples[i]
            total_us += (i * self.__samples[i])
            if self.__samples[i] > occurrences:
                occurrences = self.__samples[i]
                self.__mode = i
        self.__mean = float(total_us) / float(self.__numsamples)

        # range
        for i in keys:
            if self.__samples[i]:
                low = i
                break
        high = keys[-1]
        while high and self.__samples.get(high, 0) == 0:
            high -= 1
        self.__range = high - low

        # Mean Absolute Deviation and standard deviation
        madsum = 0
        varsum = 0
        for i in keys:
            madsum += float(abs(float(i) - self.__mean) * self.__samples[i])
            varsum += float(((float(i) - self.__mean) ** 2) * self.__samples[i])
        self.__mad = madsum / self.__numsamples
        self.__stddev = math.sqrt(varsum / (self.__numsamples - 1))


    def MakeReport(self):
        rep_n = libxml2.newNode(self.__type)
        if self.__type == 'system':
            rep_n.newProp('description', self.description)
        else:
            rep_n.newProp('id', str(self.__id))
            rep_n.newProp('priority', str(self.__priority))

        stat_n = rep_n.newChild(None, 'statistics', None)

        stat_n.newTextChild(None, 'samples', str(self.__numsamples))

        if self.__numsamples > 0:
            n = stat_n.newTextChild(None, 'minimum', str(self.__min))
            n.newProp('unit', 'us')

            n = stat_n.newTextChild(None, 'maximum', str(self.__max))
            n.newProp('unit', 'us')

            n = stat_n.newTextChild(None, 'median', str(self.__median))
            n.newProp('unit', 'us')

            n = stat_n.newTextChild(None, 'mode', str(self.__mode))
            n.newProp('unit', 'us')

            n = stat_n.newTextChild(None, 'range', str(self.__range))
            n.newProp('unit', 'us')

            n = stat_n.newTextChild(None, 'mean', str(self.__mean))
            n.newProp('unit', 'us')

            n = stat_n.newTextChild(None, 'mean_absolute_deviation', str(self.__mad))
            n.newProp('unit', 'us')

            n = stat_n.newTextChild(None, 'standard_deviation', str(self.__stddev))
            n.newProp('unit', 'us')

            hist_n = rep_n.newChild(None, 'histogram', None)
            hist_n.newProp('nbuckets', str(len(self.__samples)))
            keys = list(self.__samples.keys())
            keys.sort()
            for k in keys:
                if self.__samples[k] == 0:
                    # Don't report buckets without any samples
                    continue
                b_n = hist_n.newChild(None, 'bucket', None)
                b_n.newProp('index', str(k))
                b_n.newProp('value', str(self.__samples[k]))

        return rep_n


class Cyclictest(rtevalModulePrototype):
    """ measurement module for rteval """
    def __init__(self, config, logger=None):
        rtevalModulePrototype.__init__(self, 'measurement', 'cyclictest', logger)
        self.__cfg = config

        # Create a RunData object per CPU core
        self.__numanodes = int(self.__cfg.setdefault('numanodes', 0))
        self.__priority = int(self.__cfg.setdefault('priority', 95))
        default_buckets = ModuleParameters()["buckets"]["default"]
        self.__buckets = int(self.__cfg.setdefault('buckets', default_buckets))
        self.__numcores = 0
        self.__cyclicdata = {}
        self.__cpulist = self.__cfg.setdefault('cpulist', "")
        self.__cpus = [str(c) for c in expand_cpulist(self.__cpulist)]
        self.__numcores = len(self.__cpus)

        info = cpuinfo()

        # create a RunData object for each core we'll measure
        for core in self.__cpus:
            self.__cyclicdata[core] = RunData(core, 'core', self.__priority,
                                              logfnc=self._log)
            self.__cyclicdata[core].description = info[core]['model name']

        # Create a RunData object for the overall system
        self.__cyclicdata['system'] = RunData('system',
                                              'system', self.__priority,
                                              logfnc=self._log)
        self.__cyclicdata['system'].description = (f"({self.__numcores} cores) ") + info['0']['model name']

        self._log(Log.DEBUG, f"system using {self.__numcores} cpu cores")
        self.__started = False
        self.__cyclicoutput = None
        self.__breaktraceval = None
        self.set_latency_test()


    @staticmethod
    def __get_debugfs_mount():
        ret = None
        with open('/proc/mounts') as mounts:
            for l in mounts:
                field = l.split()
                if field[2] == "debugfs":
                    ret = field[1]
                    break
            return ret


    def _WorkloadSetup(self):
        self.__cyclicprocess = None


    def _WorkloadBuild(self):
        self._setReady()


    def _WorkloadPrepare(self):
        self.__interval = 'interval' in self.__cfg and f'-i{int(self.__cfg.interval)}' or ""

        self.__cmd = ['cyclictest',
                      self.__interval,
                      '-qmu',
                      f'-h {self.__buckets}',
                      f"-p{int(self.__priority)}",
                      ]
        self.__cmd.append(f'-t{self.__numcores}')
        self.__cmd.append(f'-a{self.__cpulist}')

        if (self.__cfg.usingCpupower):
            self.__cmd.append('--default-system')

        if 'threads' in self.__cfg and self.__cfg.threads:
            self.__cmd.append(f"-t{int(self.__cfg.threads)}")

        # Should have either breaktrace or threshold, not both
        if 'breaktrace' in self.__cfg and self.__cfg.breaktrace:
            self.__cmd.append(f"-b{int(self.__cfg.breaktrace)}")
            self.__cmd.append("--tracemark")
        elif self.__cfg.threshold:
            self.__cmd.append(f"-b{int(self.__cfg.threshold)}")

        # Buffer for cyclictest data written to stdout
        self.__cyclicoutput = tempfile.SpooledTemporaryFile(mode='w+b')


    def _WorkloadTask(self):
        if self.__started:
            # Don't restart cyclictest if it is already running
            return

        self._log(Log.DEBUG, f'starting with cmd: {" ".join(self.__cmd)}')
        self.__nullfp = os.open('/dev/null', os.O_RDWR)

        debugdir = self.__get_debugfs_mount()
        if 'breaktrace' in self.__cfg and self.__cfg.breaktrace and debugdir:
            # Ensure that the trace log is clean
            trace = os.path.join(debugdir, 'tracing', 'trace')
            with open(os.path.join(trace), "w") as fp:
                fp.write("0")
                fp.flush()

        self.__cyclicoutput.seek(0)
        self.__cyclicprocess = subprocess.Popen(self.__cmd,
                                                stdout=self.__cyclicoutput,
                                                stderr=self.__nullfp,
                                                stdin=self.__nullfp)
        self.__started = True

    def WorkloadAlive(self):
        if self.__started:
            return self.__cyclicprocess.poll() is None
        return False


    def _parse_max_latencies(self, line):
        if not line.startswith('# Max Latencies: '):
            return

        line = line.split(':')[1]
        vals = [int(x) for x in line.split()]

        for i, core in enumerate(self.__cpus):
            self.__cyclicdata[core].update_max(vals[i])
            self.__cyclicdata['system'].update_max(vals[i])


    def _WorkloadCleanup(self):
        if not self.__started:
            return
        while self.__cyclicprocess.poll() is None:
            self._log(Log.DEBUG, "Sending SIGINT")
            os.kill(self.__cyclicprocess.pid, signal.SIGINT)
            time.sleep(2)

        # now parse the histogram output
        self.__cyclicoutput.seek(0)
        for line in self.__cyclicoutput:
            line = bytes.decode(line)
            if line.startswith('#'):
                # Catch if cyclictest stopped due to a breaktrace
                if line.startswith('# Break value: '):
                    self.__breaktraceval = int(line.split(':')[1])
                elif line.startswith('# Max Latencies: '):
                    self._parse_max_latencies(line)
                continue

            # Skipping blank lines
            if not line:
                continue

            vals = line.split()
            if not vals:
                # If we don't have any values, don't try parsing
                continue

            try:
                index = int(vals[0])
            except:
                self._log(Log.DEBUG, f"cyclictest: unexpected output: {line}")
                continue

            for i, core in enumerate(self.__cpus):
                self.__cyclicdata[core].bucket(index, int(vals[i+1]))
                self.__cyclicdata['system'].bucket(index, int(vals[i+1]))

        # generate statistics for each RunData object
        for n in list(self.__cyclicdata.keys()):
            #print "reducing self.__cyclicdata[%s]" % n
            self.__cyclicdata[n].reduce()
            #print self.__cyclicdata[n]

        self._setFinished()
        self.__started = False
        os.close(self.__nullfp)
        del self.__nullfp


    def MakeReport(self):
        rep_n = libxml2.newNode('cyclictest')
        rep_n.newProp('command_line', ' '.join(self.__cmd))

        # If it was detected cyclictest was aborted somehow,
        # report the reason
        abrt_n = libxml2.newNode('abort_report')
        abrt = False
        if self.__breaktraceval:
            abrt_n.newProp('reason', 'breaktrace')
            btv_n = abrt_n.newChild(None, 'breaktrace', None)
            btv_n.newProp('latency_threshold', str(self.__cfg.breaktrace) if self.__cfg.breaktrace else str(self.__cfg.threshold))
            btv_n.newProp('measured_latency', str(self.__breaktraceval))
            abrt = True

        # Only add the <abort_report/> node if an abortion happened
        if abrt:
            rep_n.addChild(abrt_n)

        # Let the user know if max latency overshot the number of buckets
        if self.__cyclicdata["system"].get_max() > self.__buckets:
            self._log(Log.ERR, f'Max latency({self.__cyclicdata["system"].get_max()}us) exceeded histogram range({self.__buckets}us). Skipping statistics')
            self._log(Log.ERR, "Increase number of buckets to avoid lost samples")
            return rep_n

        rep_n.addChild(self.__cyclicdata["system"].MakeReport())
        for thr in self.__cpus:
            if str(thr) not in self.__cyclicdata:
                continue
            rep_n.addChild(self.__cyclicdata[str(thr)].MakeReport())

        return rep_n


def ModuleParameters():
    """ default parameters """
    return {"interval": {"descr": "Base interval of the threads in microseconds",
                         "default": 100,
                         "metavar": "INTV_US"},
            "buckets":  {"descr": "Histogram width",
                         "default": 3500,
                         "metavar": "NUM"},
            "priority": {"descr": "Run cyclictest with the given priority",
                         "default": 95,
                         "metavar": "PRIO"},
            "breaktrace": {"descr": "Send a break trace command when latency > USEC",
                           "default": None,
                           "metavar": "USEC"},
            "threshold": {"descr": "Exit rteval if latency > USEC",
                          "default": None,
                          "metavar": "USEC"}
            }



def create(params, logger):
    """ Instantiate a Cyclictest measurement module object """
    return Cyclictest(params, logger)


if __name__ == '__main__':
    from rteval.rtevalConfig import rtevalConfig

    l = Log()
    l.SetLogVerbosity(Log.INFO|Log.DEBUG|Log.ERR|Log.WARN)

    cfg = rtevalConfig({}, logger=l)
    prms = {}
    modprms = ModuleParameters()
    for c, p in list(modprms.items()):
        prms[c] = p['default']
    cfg.AppendConfig('cyclictest', prms)

    cfg_ct = cfg.GetSection('cyclictest')
    cfg_ct.cpulist = collapse_cpulist(SysTopology().online_cpus())

    runtime = 10

    c = Cyclictest(cfg_ct, l)
    c._WorkloadSetup()
    c._WorkloadPrepare()
    c._WorkloadTask()
    time.sleep(runtime)
    c._WorkloadCleanup()
    rep_n = c.MakeReport()

    xml = libxml2.newDoc('1.0')
    xml.setRootElement(rep_n)
    xml.saveFormatFileEnc('-', 'UTF-8', 1)
