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tools/kvm_stat: move functions to corresponding classes

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Quite a few of the functions are used only in a single class. Moving
functions accordingly to improve the overall structure.
Furthermore, introduce a base class for the providers, which might also
come handy for future extensions.

Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Stefan Raspl 2017-06-07 21:08:33 +02:00 committed by Paolo Bonzini
parent c469117df0
commit 099a2dfc67
1 changed files with 165 additions and 162 deletions
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327
tools/kvm/kvm_stat/kvm_stat
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@ -295,121 +295,6 @@ class ArchS390(Arch):
ARCH = Arch.get_arch()
def is_field_wanted(fields_filter, field):
"""Indicate whether field is valid according to fields_filter."""
if not fields_filter:
return True
return re.match(fields_filter, field) is not None
def walkdir(path):
"""Returns os.walk() data for specified directory.
As it is only a wrapper it returns the same 3-tuple of (dirpath,
dirnames, filenames).
"""
return next(os.walk(path))
def parse_int_list(list_string):
"""Returns an int list from a string of comma separated integers and
integer ranges."""
integers = []
members = list_string.split(',')
for member in members:
if '-' not in member:
integers.append(int(member))
else:
int_range = member.split('-')
integers.extend(range(int(int_range[0]),
int(int_range[1]) + 1))
return integers
def get_pid_from_gname(gname):
"""Fuzzy function to convert guest name to QEMU process pid.
Returns a list of potential pids, can be empty if no match found.
Throws an exception on processing errors.
"""
pids = []
try:
child = subprocess.Popen(['ps', '-A', '--format', 'pid,args'],
stdout=subprocess.PIPE)
except:
raise Exception
for line in child.stdout:
line = line.lstrip().split(' ', 1)
# perform a sanity check before calling the more expensive
# function to possibly extract the guest name
if ' -name ' in line[1] and gname == get_gname_from_pid(line[0]):
pids.append(int(line[0]))
child.stdout.close()
return pids
def get_gname_from_pid(pid):
"""Returns the guest name for a QEMU process pid.
Extracts the guest name from the QEMU comma line by processing the '-name'
option. Will also handle names specified out of sequence.
"""
name = ''
try:
line = open('/proc/{}/cmdline'.format(pid), 'rb').read().split('\0')
parms = line[line.index('-name') + 1].split(',')
while '' in parms:
# commas are escaped (i.e. ',,'), hence e.g. 'foo,bar' results in
# ['foo', '', 'bar'], which we revert here
idx = parms.index('')
parms[idx - 1] += ',' + parms[idx + 1]
del parms[idx:idx+2]
# the '-name' switch allows for two ways to specify the guest name,
# where the plain name overrides the name specified via 'guest='
for arg in parms:
if '=' not in arg:
name = arg
break
if arg[:6] == 'guest=':
name = arg[6:]
except (ValueError, IOError, IndexError):
pass
return name
def get_online_cpus():
"""Returns a list of cpu id integers."""
with open('/sys/devices/system/cpu/online') as cpu_list:
cpu_string = cpu_list.readline()
return parse_int_list(cpu_string)
def get_filters():
"""Returns a dict of trace events, their filter ids and
the values that can be filtered.
Trace events can be filtered for special values by setting a
filter string via an ioctl. The string normally has the format
identifier==value. For each filter a new event will be created, to
be able to distinguish the events.
"""
filters = {}
filters['kvm_userspace_exit'] = ('reason', USERSPACE_EXIT_REASONS)
if ARCH.exit_reasons:
filters['kvm_exit'] = ('exit_reason', ARCH.exit_reasons)
return filters
libc = ctypes.CDLL('libc.so.6', use_errno=True)
syscall = libc.syscall
class perf_event_attr(ctypes.Structure):
"""Struct that holds the necessary data to set up a trace event.
@ -439,25 +324,6 @@ class perf_event_attr(ctypes.Structure):
self.read_format = PERF_FORMAT_GROUP
def perf_event_open(attr, pid, cpu, group_fd, flags):
"""Wrapper for the sys_perf_evt_open() syscall.
Used to set up performance events, returns a file descriptor or -1
on error.
Attributes are:
- syscall number
- struct perf_event_attr *
- pid or -1 to monitor all pids
- cpu number or -1 to monitor all cpus
- The file descriptor of the group leader or -1 to create a group.
- flags
"""
return syscall(ARCH.sc_perf_evt_open, ctypes.pointer(attr),
ctypes.c_int(pid), ctypes.c_int(cpu),
ctypes.c_int(group_fd), ctypes.c_long(flags))
PERF_TYPE_TRACEPOINT = 2
PERF_FORMAT_GROUP = 1 << 3
@ -502,6 +368,8 @@ class Event(object):
"""Represents a performance event and manages its life cycle."""
def __init__(self, name, group, trace_cpu, trace_pid, trace_point,
trace_filter, trace_set='kvm'):
self.libc = ctypes.CDLL('libc.so.6', use_errno=True)
self.syscall = self.libc.syscall
self.name = name
self.fd = None
self.setup_event(group, trace_cpu, trace_pid, trace_point,
@ -518,6 +386,25 @@ class Event(object):
if self.fd:
os.close(self.fd)
def perf_event_open(self, attr, pid, cpu, group_fd, flags):
"""Wrapper for the sys_perf_evt_open() syscall.
Used to set up performance events, returns a file descriptor or -1
on error.
Attributes are:
- syscall number
- struct perf_event_attr *
- pid or -1 to monitor all pids
- cpu number or -1 to monitor all cpus
- The file descriptor of the group leader or -1 to create a group.
- flags
"""
return self.syscall(ARCH.sc_perf_evt_open, ctypes.pointer(attr),
ctypes.c_int(pid), ctypes.c_int(cpu),
ctypes.c_int(group_fd), ctypes.c_long(flags))
def setup_event_attribute(self, trace_set, trace_point):
"""Returns an initialized ctype perf_event_attr struct."""
@ -546,8 +433,8 @@ class Event(object):
if group.events:
group_leader = group.events[0].fd
fd = perf_event_open(event_attr, trace_pid,
trace_cpu, group_leader, 0)
fd = self.perf_event_open(event_attr, trace_pid,
trace_cpu, group_leader, 0)
if fd == -1:
err = ctypes.get_errno()
raise OSError(err, os.strerror(err),
@ -582,7 +469,26 @@ class Event(object):
fcntl.ioctl(self.fd, ARCH.ioctl_numbers['RESET'], 0)
class TracepointProvider(object):
class Provider(object):
"""Encapsulates functionalities used by all providers."""
@staticmethod
def is_field_wanted(fields_filter, field):
"""Indicate whether field is valid according to fields_filter."""
if not fields_filter:
return True
return re.match(fields_filter, field) is not None
@staticmethod
def walkdir(path):
"""Returns os.walk() data for specified directory.
As it is only a wrapper it returns the same 3-tuple of (dirpath,
dirnames, filenames).
"""
return next(os.walk(path))
class TracepointProvider(Provider):
"""Data provider for the stats class.
Manages the events/groups from which it acquires its data.
@ -590,10 +496,27 @@ class TracepointProvider(object):
"""
def __init__(self, pid, fields_filter):
self.group_leaders = []
self.filters = get_filters()
self.filters = self.get_filters()
self.update_fields(fields_filter)
self.pid = pid
@staticmethod
def get_filters():
"""Returns a dict of trace events, their filter ids and
the values that can be filtered.
Trace events can be filtered for special values by setting a
filter string via an ioctl. The string normally has the format
identifier==value. For each filter a new event will be created, to
be able to distinguish the events.
"""
filters = {}
filters['kvm_userspace_exit'] = ('reason', USERSPACE_EXIT_REASONS)
if ARCH.exit_reasons:
filters['kvm_exit'] = ('exit_reason', ARCH.exit_reasons)
return filters
def get_available_fields(self):
"""Returns a list of available event's of format 'event name(filter
name)'.
@ -610,7 +533,7 @@ class TracepointProvider(object):
"""
path = os.path.join(PATH_DEBUGFS_TRACING, 'events', 'kvm')
fields = walkdir(path)[1]
fields = self.walkdir(path)[1]
extra = []
for field in fields:
if field in self.filters:
@ -623,7 +546,30 @@ class TracepointProvider(object):
def update_fields(self, fields_filter):
"""Refresh fields, applying fields_filter"""
self._fields = [field for field in self.get_available_fields()
if is_field_wanted(fields_filter, field)]
if self.is_field_wanted(fields_filter, field)]
@staticmethod
def get_online_cpus():
"""Returns a list of cpu id integers."""
def parse_int_list(list_string):
"""Returns an int list from a string of comma separated integers and
integer ranges."""
integers = []
members = list_string.split(',')
for member in members:
if '-' not in member:
integers.append(int(member))
else:
int_range = member.split('-')
integers.extend(range(int(int_range[0]),
int(int_range[1]) + 1))
return integers
with open('/sys/devices/system/cpu/online') as cpu_list:
cpu_string = cpu_list.readline()
return parse_int_list(cpu_string)
def setup_traces(self):
"""Creates all event and group objects needed to be able to retrieve
@ -633,9 +579,9 @@ class TracepointProvider(object):
# Fetch list of all threads of the monitored pid, as qemu
# starts a thread for each vcpu.
path = os.path.join('/proc', str(self._pid), 'task')
groupids = walkdir(path)[1]
groupids = self.walkdir(path)[1]
else:
groupids = get_online_cpus()
groupids = self.get_online_cpus()
# The constant is needed as a buffer for python libs, std
# streams and other files that the script opens.
@ -732,7 +678,7 @@ class TracepointProvider(object):
event.reset()
class DebugfsProvider(object):
class DebugfsProvider(Provider):
"""Provides data from the files that KVM creates in the kvm debugfs
folder."""
def __init__(self, pid, fields_filter):
@ -748,12 +694,12 @@ class DebugfsProvider(object):
The fields are all available KVM debugfs files
"""
return walkdir(PATH_DEBUGFS_KVM)[2]
return self.walkdir(PATH_DEBUGFS_KVM)[2]
def update_fields(self, fields_filter):
"""Refresh fields, applying fields_filter"""
self._fields = [field for field in self.get_available_fields()
if is_field_wanted(fields_filter, field)]
if self.is_field_wanted(fields_filter, field)]
@property
def fields(self):
@ -772,7 +718,7 @@ class DebugfsProvider(object):
def pid(self, pid):
self._pid = pid
if pid != 0:
vms = walkdir(PATH_DEBUGFS_KVM)[1]
vms = self.walkdir(PATH_DEBUGFS_KVM)[1]
if len(vms) == 0:
self.do_read = False
@ -834,11 +780,23 @@ class Stats(object):
"""
def __init__(self, options):
self.providers = get_providers(options)
self.providers = self.get_providers(options)
self._pid_filter = options.pid
self._fields_filter = options.fields
self.values = {}
@staticmethod
def get_providers(options):
"""Returns a list of data providers depending on the passed options."""
providers = []
if options.debugfs:
providers.append(DebugfsProvider(options.pid, options.fields))
if options.tracepoints or not providers:
providers.append(TracepointProvider(options.pid, options.fields))
return providers
def update_provider_filters(self):
"""Propagates fields filters to providers."""
# As we reset the counters when updating the fields we can
@ -933,6 +891,63 @@ class Tui(object):
curses.nocbreak()
curses.endwin()
@staticmethod
def get_pid_from_gname(gname):
"""Fuzzy function to convert guest name to QEMU process pid.
Returns a list of potential pids, can be empty if no match found.
Throws an exception on processing errors.
"""
pids = []
try:
child = subprocess.Popen(['ps', '-A', '--format', 'pid,args'],
stdout=subprocess.PIPE)
except:
raise Exception
for line in child.stdout:
line = line.lstrip().split(' ', 1)
# perform a sanity check before calling the more expensive
# function to possibly extract the guest name
if (' -name ' in line[1] and
gname == self.get_gname_from_pid(line[0])):
pids.append(int(line[0]))
child.stdout.close()
return pids
@staticmethod
def get_gname_from_pid(pid):
"""Returns the guest name for a QEMU process pid.
Extracts the guest name from the QEMU comma line by processing the
'-name' option. Will also handle names specified out of sequence.
"""
name = ''
try:
line = open('/proc/{}/cmdline'
.format(pid), 'rb').read().split('\0')
parms = line[line.index('-name') + 1].split(',')
while '' in parms:
# commas are escaped (i.e. ',,'), hence e.g. 'foo,bar' results
# in # ['foo', '', 'bar'], which we revert here
idx = parms.index('')
parms[idx - 1] += ',' + parms[idx + 1]
del parms[idx:idx+2]
# the '-name' switch allows for two ways to specify the guest name,
# where the plain name overrides the name specified via 'guest='
for arg in parms:
if '=' not in arg:
name = arg
break
if arg[:6] == 'guest=':
name = arg[6:]
except (ValueError, IOError, IndexError):
pass
return name
def update_drilldown(self):
"""Sets or removes a filter that only allows fields without braces."""
if not self.stats.fields_filter:
@ -950,7 +965,7 @@ class Tui(object):
if pid is None:
pid = self.stats.pid_filter
self.screen.erase()
gname = get_gname_from_pid(pid)
gname = self.get_gname_from_pid(pid)
if gname:
gname = ('({})'.format(gname[:MAX_GUEST_NAME_LEN] + '...'
if len(gname) > MAX_GUEST_NAME_LEN
@ -1096,7 +1111,7 @@ class Tui(object):
else:
pids = []
try:
pids = get_pid_from_gname(gname)
pids = self.get_pid_from_gname(gname)
except:
msg = '"' + gname + '": Internal error while searching, ' \
'use pid filter instead'
@ -1229,7 +1244,7 @@ Press any other key to refresh statistics immediately.
def cb_guest_to_pid(option, opt, val, parser):
try:
pids = get_pid_from_gname(val)
pids = Tui.get_pid_from_gname(val)
except:
raise optparse.OptionValueError('Error while searching for guest '
'"{}", use "-p" to specify a pid '
@ -1294,18 +1309,6 @@ Press any other key to refresh statistics immediately.
return options
def get_providers(options):
"""Returns a list of data providers depending on the passed options."""
providers = []
if options.debugfs:
providers.append(DebugfsProvider(options.pid, options.fields))
if options.tracepoints or not providers:
providers.append(TracepointProvider(options.pid, options.fields))
return providers
def check_access(options):
"""Exits if the current user can't access all needed directories."""
if not os.path.exists('/sys/kernel/debug'):