contrib/gen_autofdo_event.py

   1 #!/usr/bin/python3
   2 # Generate Intel taken branches Linux perf event script for autofdo profiling.
   3
   4 # Copyright (C) 2016-2023 Free Software Foundation, Inc.
   5 #
   6 # GCC is free software; you can redistribute it and/or modify it under
   7 # the terms of the GNU General Public License as published by the Free
   8 # Software Foundation; either version 3, or (at your option) any later
   9 # version.
  10 #
  11 # GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 # WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 # for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with GCC; see the file COPYING3.  If not see
  18 # <http://www.gnu.org/licenses/>.  */
  19
  20 # Run it with perf record -b -e EVENT program ...
  21 # The Linux Kernel needs to support the PMU of the current CPU, and
  22 # It will likely not work in VMs.
  23 # Add --all to print for all cpus, otherwise for current cpu.
  24 # Add --script to generate shell script to run correct event.
  25 #
  26 # Requires internet (https) access. This may require setting up a proxy
  27 # with export https_proxy=...
  28 #
  29 import urllib.request
  30 import sys
  31 import json
  32 import argparse
  33 import collections
  34 import os
  35
  36 baseurl = "https://download.01.org/perfmon"
  37
  38 target_events = ('BR_INST_RETIRED.NEAR_TAKEN',
  39                  'BR_INST_EXEC.TAKEN',
  40                  'BR_INST_RETIRED.TAKEN_JCC',
  41                  'BR_INST_TYPE_RETIRED.COND_TAKEN')
  42
  43 ap = argparse.ArgumentParser()
  44 ap.add_argument('--all', '-a', help='Print for all CPUs', action='store_true')
  45 ap.add_argument('--script', help='Generate shell script', action='store_true')
  46 args = ap.parse_args()
  47
  48 eventmap = collections.defaultdict(list)
  49
  50 def get_cpustr():
  51     cpuinfo = os.getenv("CPUINFO")
  52     if cpuinfo is None:
  53         cpuinfo = '/proc/cpuinfo'
  54     f = open(cpuinfo, 'r')
  55     cpu = [None, None, None, None]
  56     for j in f:
  57         n = j.split()
  58         if n[0] == 'vendor_id':
  59             cpu[0] = n[2]
  60         elif n[0] == 'model' and n[1] == ':':
  61             cpu[2] = int(n[2])
  62         elif n[0] == 'cpu' and n[1] == 'family':
  63             cpu[1] = int(n[3])
  64         elif n[0] == 'stepping' and n[1] == ':':
  65             cpu[3] = int(n[2])
  66         if all(v is not None for v in cpu):
  67             break
  68     # stepping for SKX only
  69     stepping = cpu[0] == "GenuineIntel" and cpu[1] == 6 and cpu[2] == 0x55
  70     if stepping:
  71         return "%s-%d-%X-%X" % tuple(cpu)
  72     return "%s-%d-%X" % tuple(cpu)[:3]
  73
  74 def find_event(eventurl, model):
  75     print("Downloading", eventurl, file = sys.stderr)
  76     u = urllib.request.urlopen(eventurl)
  77     events = json.loads(u.read())
  78     u.close()
  79
  80     found = 0
  81     for j in events:
  82         if j['EventName'] in target_events:
  83             event = "cpu/event=%s,umask=%s/" % (j['EventCode'], j['UMask'])
  84             if 'PEBS' in j and int(j['PEBS']) > 0:
  85                 event += "p"
  86             if args.script:
  87                 eventmap[event].append(model)
  88             else:
  89                 print(j['EventName'], "event for model", model, "is", event)
  90             found += 1
  91     return found
  92
  93 if not args.all:
  94     cpu = get_cpustr()
  95     if not cpu:
  96         sys.exit("Unknown CPU type")
  97
  98 url = baseurl + "/mapfile.csv"
  99 print("Downloading", url, file = sys.stderr)
 100 u = urllib.request.urlopen(url)
 101 found = 0
 102 cpufound = 0
 103 for j in u:
 104     n = j.rstrip().decode().split(',')
 105     if len(n) >= 4 and (args.all or n[0] == cpu) and n[3] == "core":
 106         components = n[0].split("-")
 107         model = components[2]
 108         model = int(model, 16)
 109         cpufound += 1
 110         found += find_event(baseurl + n[2], model)
 111 u.close()
 112
 113 if args.script:
 114     print('''#!/bin/sh
 115 # Profile workload for gcc profile feedback (autofdo) using Linux perf.
 116 # Auto generated. To regenerate for new CPUs run
 117 # contrib/gen_autofdo_event.py --script --all in gcc source
 118
 119 # usages:
 120 # gcc-auto-profile program             (profile program and children)
 121 # gcc-auto-profile -a sleep X          (profile all for X secs, may need root)
 122 # gcc-auto-profile -p PID sleep X      (profile PID)
 123 # gcc-auto-profile --kernel -a sleep X (profile kernel)
 124 # gcc-auto-profile --all -a sleep X    (profile kernel and user space)
 125
 126 # Identify branches taken event for CPU.
 127 #
 128
 129 FLAGS=u
 130
 131 if [ "$1" = "--kernel" ] ; then
 132   FLAGS=k
 133   shift
 134 fi
 135 if [ "$1" = "--all" ] ; then
 136   FLAGS=uk
 137   shift
 138 fi
 139
 140 if ! grep -q Intel /proc/cpuinfo ; then
 141   echo >&2 "Only Intel CPUs supported"
 142   exit 1
 143 fi
 144
 145 if grep -q hypervisor /proc/cpuinfo ; then
 146   echo >&2 "Warning: branch profiling may not be functional in VMs"
 147 fi
 148
 149 case `grep -E -q "^cpu family\s*: 6" /proc/cpuinfo &&
 150   grep -E "^model\s*:" /proc/cpuinfo | head -n1` in''')
 151     for event, mod in eventmap.items():
 152         for m in mod[:-1]:
 153             print("model*:\ %s|\\" % m)
 154         print('model*:\ %s) E="%s$FLAGS" ;;' % (mod[-1], event))
 155     print('''*)
 156 echo >&2 "Unknown CPU. Run contrib/gen_autofdo_event.py --all --script to update script."
 157         exit 1 ;;''')
 158     print("esac")
 159     print("set -x")
 160     print('if ! perf record -e $E -b "$@" ; then')
 161     print('  # PEBS may not actually be working even if the processor supports it')
 162     print('  # (e.g., in a virtual machine). Trying to run without /p.')
 163     print('  set +x')
 164     print('  echo >&2 "Retrying without /p."')
 165     print('  E="$(echo "${E}" | sed -e \'s/\/p/\//\')"')
 166     print('  set -x')
 167     print('  exec perf record -e $E -b "$@"')
 168     print(' set +x')
 169     print('fi')
 170
 171 if cpufound == 0 and not args.all:
 172     sys.exit('CPU %s not found' % cpu)
 173
 174 if found == 0:
 175     sys.exit('Branch event not found')