Update gen_autofdo_event.py and gcc-auto-profile.

gen_autofdo_event.py was stumbling on models with stepping so
I updated the script to handle this case similar to the code in
c6a5f63aed/event_download.py

The second change was to tolerate cases when the CPU supports PEBS but the
perf command with /p fails. This can happen in, e.g., a virtual machine.

I regenerated gcc-auto-profile using the updated script.

contrib/ChangeLog:

	* gen_autofdo_event.py: handle stepping, non-working PEBS

gcc/ChangeLog:

	* config/i386/gcc-auto-profile: regenerate

contrib/gen_autofdo_event.py

@@ -46,20 +46,29 @@ args = ap.parse_args()
 
 eventmap = collections.defaultdict(list)
 
-def get_cpu_str():
-    with open('/proc/cpuinfo', 'r') as c:
-        vendor, fam, model = None, None, None
-        for j in c:
-            n = j.split()
-            if n[0] == 'vendor_id':
-                vendor = n[2]
-            elif n[0] == 'model' and n[1] == ':':
-                model = int(n[2])
-            elif n[0] == 'cpu' and n[1] == 'family':
-                fam = int(n[3])
-            if vendor and fam and model:
-                return "%s-%d-%X" % (vendor, fam, model), model
-    return None, None
+def get_cpustr():
+    cpuinfo = os.getenv("CPUINFO")
+    if cpuinfo is None:
+        cpuinfo = '/proc/cpuinfo'
+    f = open(cpuinfo, 'r')
+    cpu = [None, None, None, None]
+    for j in f:
+        n = j.split()
+        if n[0] == 'vendor_id':
+            cpu[0] = n[2]
+        elif n[0] == 'model' and n[1] == ':':
+            cpu[2] = int(n[2])
+        elif n[0] == 'cpu' and n[1] == 'family':
+            cpu[1] = int(n[3])
+        elif n[0] == 'stepping' and n[1] == ':':
+            cpu[3] = int(n[2])
+        if all(v is not None for v in cpu):
+            break
+    # stepping for SKX only
+    stepping = cpu[0] == "GenuineIntel" and cpu[1] == 6 and cpu[2] == 0x55
+    if stepping:
+        return "%s-%d-%X-%X" % tuple(cpu)
+    return "%s-%d-%X" % tuple(cpu)[:3]
 
 def find_event(eventurl, model):
     print >>sys.stderr, "Downloading", eventurl
@@ -81,7 +90,7 @@ def find_event(eventurl, model):
     return found
 
 if not args.all:
-    cpu, model = get_cpu_str()
+    cpu = get_cpu_str()
     if not cpu:
         sys.exit("Unknown CPU type")
 
@@ -94,7 +103,8 @@ for j in u:
     n = j.rstrip().split(',')
     if len(n) >= 4 and (args.all or n[0] == cpu) and n[3] == "core":
         if args.all:
-            vendor, fam, model = n[0].split("-")
+            components = n[0].split("-")
+            model = components[2]
             model = int(model, 16)
         cpufound += 1
         found += find_event(baseurl + n[2], model)
@@ -146,7 +156,17 @@ case `egrep -q "^cpu family\s*: 6" /proc/cpuinfo &&
 echo >&2 "Unknown CPU. Run contrib/gen_autofdo_event.py --all --script to update script."
 	exit 1 ;;'''
     print "esac"
-    print 'exec perf record -e $E -b "$@"'
+    print "set -x"
+    print 'if ! perf record -e $E -b "$@" ; then'
+    print '  # PEBS may not actually be working even if the processor supports it'
+    print '  # (e.g., in a virtual machine). Trying to run without /p.'
+    print '  set +x'
+    print '  echo >&2 "Retrying without /p."'
+    print '  E="$(echo "${E}" | sed -e \'s/\/p/\//\')"'
+    print '  set -x'
+    print '  exec perf record -e $E -b "$@"'
+    print ' set +x'
+    print 'fi'
 
 if cpufound == 0 and not args.all:
     sys.exit('CPU %s not found' % cpu)

gcc/config/i386/gcc-auto-profile

@@ -1,7 +1,7 @@
 #!/bin/sh
-# profile workload for gcc profile feedback (autofdo) using Linux perf
-# auto generated. to regenerate for new CPUs run
-# contrib/gen_autofdo_event.py --shell --all in gcc source
+# Profile workload for gcc profile feedback (autofdo) using Linux perf.
+# Auto generated. To regenerate for new CPUs run
+# contrib/gen_autofdo_event.py --script --all in gcc source
 
 # usages:
 # gcc-auto-profile program             (profile program and children)
@@ -10,7 +10,7 @@
 # gcc-auto-profile --kernel -a sleep X (profile kernel)
 # gcc-auto-profile --all -a sleep X    (profile kernel and user space)
 
-# identify branches taken event for CPU
+# Identify branches taken event for CPU.
 #
 
 FLAGS=u
@@ -37,7 +37,12 @@ case `egrep -q "^cpu family\s*: 6" /proc/cpuinfo &&
   egrep "^model\s*:" /proc/cpuinfo | head -n1` in
 model*:\ 55|\
 model*:\ 77|\
-model*:\ 76) E="cpu/event=0xC4,umask=0xFE/p$FLAGS" ;;
+model*:\ 76|\
+model*:\ 92|\
+model*:\ 95|\
+model*:\ 87|\
+model*:\ 133|\
+model*:\ 122) E="cpu/event=0xC4,umask=0xFE/p$FLAGS" ;;
 model*:\ 42|\
 model*:\ 45|\
 model*:\ 58|\
@@ -48,9 +53,16 @@ model*:\ 70|\
 model*:\ 63|\
 model*:\ 61|\
 model*:\ 71|\
+model*:\ 79|\
 model*:\ 86|\
 model*:\ 78|\
-model*:\ 94) E="cpu/event=0xC4,umask=0x20/p$FLAGS" ;;
+model*:\ 94|\
+model*:\ 142|\
+model*:\ 158|\
+model*:\ 165|\
+model*:\ 166|\
+model*:\ 85|\
+model*:\ 85) E="cpu/event=0xC4,umask=0x20/p$FLAGS" ;;
 model*:\ 46|\
 model*:\ 30|\
 model*:\ 31|\
@@ -63,8 +75,23 @@ model*:\ 38|\
 model*:\ 39|\
 model*:\ 54|\
 model*:\ 53) E="cpu/event=0x88,umask=0x41/p$FLAGS" ;;
+model*:\ 126|\
+model*:\ 140|\
+model*:\ 141|\
+model*:\ 106|\
+model*:\ 108) E="cpu/event=0xc4,umask=0x20/p$FLAGS" ;;
 *)
 echo >&2 "Unknown CPU. Run contrib/gen_autofdo_event.py --all --script to update script."
 	exit 1 ;;
 esac
-exec perf record -e $E -b "$@"
+set -x
+if ! perf record -e $E -b "$@" ; then
+  # PEBS may not actually be working even if the processor supports it
+  # (e.g., in a virtual machine). Trying to run without /p.
+  set +x
+  echo >&2 "Retrying without /p."
+  E="$(echo "${E}" | sed -e 's/\/p/\//')"
+  set -x
+  exec perf record -e $E -b "$@"
+ set +x
+fi