summaryrefslogtreecommitdiff
path: root/tools/kvm/kvm_stat/kvm_stat
blob: 769d884b6d94ccc6c69399b2ea3ed6c206c87887 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
#!/usr/bin/python
#
# top-like utility for displaying kvm statistics
#
# Copyright 2006-2008 Qumranet Technologies
# Copyright 2008-2011 Red Hat, Inc.
#
# Authors:
#  Avi Kivity <avi@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.  See
# the COPYING file in the top-level directory.

import curses
import sys
import os
import time
import optparse
import ctypes
import fcntl
import resource
import struct
import re
from collections import defaultdict
from time import sleep

VMX_EXIT_REASONS = {
    'EXCEPTION_NMI':        0,
    'EXTERNAL_INTERRUPT':   1,
    'TRIPLE_FAULT':         2,
    'PENDING_INTERRUPT':    7,
    'NMI_WINDOW':           8,
    'TASK_SWITCH':          9,
    'CPUID':                10,
    'HLT':                  12,
    'INVLPG':               14,
    'RDPMC':                15,
    'RDTSC':                16,
    'VMCALL':               18,
    'VMCLEAR':              19,
    'VMLAUNCH':             20,
    'VMPTRLD':              21,
    'VMPTRST':              22,
    'VMREAD':               23,
    'VMRESUME':             24,
    'VMWRITE':              25,
    'VMOFF':                26,
    'VMON':                 27,
    'CR_ACCESS':            28,
    'DR_ACCESS':            29,
    'IO_INSTRUCTION':       30,
    'MSR_READ':             31,
    'MSR_WRITE':            32,
    'INVALID_STATE':        33,
    'MWAIT_INSTRUCTION':    36,
    'MONITOR_INSTRUCTION':  39,
    'PAUSE_INSTRUCTION':    40,
    'MCE_DURING_VMENTRY':   41,
    'TPR_BELOW_THRESHOLD':  43,
    'APIC_ACCESS':          44,
    'EPT_VIOLATION':        48,
    'EPT_MISCONFIG':        49,
    'WBINVD':               54,
    'XSETBV':               55,
    'APIC_WRITE':           56,
    'INVPCID':              58,
}

SVM_EXIT_REASONS = {
    'READ_CR0':       0x000,
    'READ_CR3':       0x003,
    'READ_CR4':       0x004,
    'READ_CR8':       0x008,
    'WRITE_CR0':      0x010,
    'WRITE_CR3':      0x013,
    'WRITE_CR4':      0x014,
    'WRITE_CR8':      0x018,
    'READ_DR0':       0x020,
    'READ_DR1':       0x021,
    'READ_DR2':       0x022,
    'READ_DR3':       0x023,
    'READ_DR4':       0x024,
    'READ_DR5':       0x025,
    'READ_DR6':       0x026,
    'READ_DR7':       0x027,
    'WRITE_DR0':      0x030,
    'WRITE_DR1':      0x031,
    'WRITE_DR2':      0x032,
    'WRITE_DR3':      0x033,
    'WRITE_DR4':      0x034,
    'WRITE_DR5':      0x035,
    'WRITE_DR6':      0x036,
    'WRITE_DR7':      0x037,
    'EXCP_BASE':      0x040,
    'INTR':           0x060,
    'NMI':            0x061,
    'SMI':            0x062,
    'INIT':           0x063,
    'VINTR':          0x064,
    'CR0_SEL_WRITE':  0x065,
    'IDTR_READ':      0x066,
    'GDTR_READ':      0x067,
    'LDTR_READ':      0x068,
    'TR_READ':        0x069,
    'IDTR_WRITE':     0x06a,
    'GDTR_WRITE':     0x06b,
    'LDTR_WRITE':     0x06c,
    'TR_WRITE':       0x06d,
    'RDTSC':          0x06e,
    'RDPMC':          0x06f,
    'PUSHF':          0x070,
    'POPF':           0x071,
    'CPUID':          0x072,
    'RSM':            0x073,
    'IRET':           0x074,
    'SWINT':          0x075,
    'INVD':           0x076,
    'PAUSE':          0x077,
    'HLT':            0x078,
    'INVLPG':         0x079,
    'INVLPGA':        0x07a,
    'IOIO':           0x07b,
    'MSR':            0x07c,
    'TASK_SWITCH':    0x07d,
    'FERR_FREEZE':    0x07e,
    'SHUTDOWN':       0x07f,
    'VMRUN':          0x080,
    'VMMCALL':        0x081,
    'VMLOAD':         0x082,
    'VMSAVE':         0x083,
    'STGI':           0x084,
    'CLGI':           0x085,
    'SKINIT':         0x086,
    'RDTSCP':         0x087,
    'ICEBP':          0x088,
    'WBINVD':         0x089,
    'MONITOR':        0x08a,
    'MWAIT':          0x08b,
    'MWAIT_COND':     0x08c,
    'XSETBV':         0x08d,
    'NPF':            0x400,
}

# EC definition of HSR (from arch/arm64/include/asm/kvm_arm.h)
AARCH64_EXIT_REASONS = {
    'UNKNOWN':      0x00,
    'WFI':          0x01,
    'CP15_32':      0x03,
    'CP15_64':      0x04,
    'CP14_MR':      0x05,
    'CP14_LS':      0x06,
    'FP_ASIMD':     0x07,
    'CP10_ID':      0x08,
    'CP14_64':      0x0C,
    'ILL_ISS':      0x0E,
    'SVC32':        0x11,
    'HVC32':        0x12,
    'SMC32':        0x13,
    'SVC64':        0x15,
    'HVC64':        0x16,
    'SMC64':        0x17,
    'SYS64':        0x18,
    'IABT':         0x20,
    'IABT_HYP':     0x21,
    'PC_ALIGN':     0x22,
    'DABT':         0x24,
    'DABT_HYP':     0x25,
    'SP_ALIGN':     0x26,
    'FP_EXC32':     0x28,
    'FP_EXC64':     0x2C,
    'SERROR':       0x2F,
    'BREAKPT':      0x30,
    'BREAKPT_HYP':  0x31,
    'SOFTSTP':      0x32,
    'SOFTSTP_HYP':  0x33,
    'WATCHPT':      0x34,
    'WATCHPT_HYP':  0x35,
    'BKPT32':       0x38,
    'VECTOR32':     0x3A,
    'BRK64':        0x3C,
}

# From include/uapi/linux/kvm.h, KVM_EXIT_xxx
USERSPACE_EXIT_REASONS = {
    'UNKNOWN':          0,
    'EXCEPTION':        1,
    'IO':               2,
    'HYPERCALL':        3,
    'DEBUG':            4,
    'HLT':              5,
    'MMIO':             6,
    'IRQ_WINDOW_OPEN':  7,
    'SHUTDOWN':         8,
    'FAIL_ENTRY':       9,
    'INTR':             10,
    'SET_TPR':          11,
    'TPR_ACCESS':       12,
    'S390_SIEIC':       13,
    'S390_RESET':       14,
    'DCR':              15,
    'NMI':              16,
    'INTERNAL_ERROR':   17,
    'OSI':              18,
    'PAPR_HCALL':       19,
    'S390_UCONTROL':    20,
    'WATCHDOG':         21,
    'S390_TSCH':        22,
    'EPR':              23,
    'SYSTEM_EVENT':     24,
}

IOCTL_NUMBERS = {
    'SET_FILTER':  0x40082406,
    'ENABLE':      0x00002400,
    'DISABLE':     0x00002401,
    'RESET':       0x00002403,
}

class Arch(object):
    """Class that encapsulates global architecture specific data like
    syscall and ioctl numbers.

    """
    @staticmethod
    def get_arch():
        machine = os.uname()[4]

        if machine.startswith('ppc'):
            return ArchPPC()
        elif machine.startswith('aarch64'):
            return ArchA64()
        elif machine.startswith('s390'):
            return ArchS390()
        else:
            # X86_64
            for line in open('/proc/cpuinfo'):
                if not line.startswith('flags'):
                    continue

                flags = line.split()
                if 'vmx' in flags:
                    return ArchX86(VMX_EXIT_REASONS)
                if 'svm' in flags:
                    return ArchX86(SVM_EXIT_REASONS)
                return

class ArchX86(Arch):
    def __init__(self, exit_reasons):
        self.sc_perf_evt_open = 298
        self.ioctl_numbers = IOCTL_NUMBERS
        self.exit_reasons = exit_reasons

class ArchPPC(Arch):
    def __init__(self):
        self.sc_perf_evt_open = 319
        self.ioctl_numbers = IOCTL_NUMBERS
        self.ioctl_numbers['ENABLE'] = 0x20002400
        self.ioctl_numbers['DISABLE'] = 0x20002401

        # PPC comes in 32 and 64 bit and some generated ioctl
        # numbers depend on the wordsize.
        char_ptr_size = ctypes.sizeof(ctypes.c_char_p)
        self.ioctl_numbers['SET_FILTER'] = 0x80002406 | char_ptr_size << 16

class ArchA64(Arch):
    def __init__(self):
        self.sc_perf_evt_open = 241
        self.ioctl_numbers = IOCTL_NUMBERS
        self.exit_reasons = AARCH64_EXIT_REASONS

class ArchS390(Arch):
    def __init__(self):
        self.sc_perf_evt_open = 331
        self.ioctl_numbers = IOCTL_NUMBERS
        self.exit_reasons = None

ARCH = Arch.get_arch()


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_online_cpus():
    with open('/sys/devices/system/cpu/online') as cpu_list:
        cpu_string = cpu_list.readline()
        return parse_int_list(cpu_string)


def get_filters():
    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):
    _fields_ = [('type', ctypes.c_uint32),
                ('size', ctypes.c_uint32),
                ('config', ctypes.c_uint64),
                ('sample_freq', ctypes.c_uint64),
                ('sample_type', ctypes.c_uint64),
                ('read_format', ctypes.c_uint64),
                ('flags', ctypes.c_uint64),
                ('wakeup_events', ctypes.c_uint32),
                ('bp_type', ctypes.c_uint32),
                ('bp_addr', ctypes.c_uint64),
                ('bp_len', ctypes.c_uint64),
                ]

    def __init__(self):
        super(self.__class__, self).__init__()
        self.type = PERF_TYPE_TRACEPOINT
        self.size = ctypes.sizeof(self)
        self.read_format = PERF_FORMAT_GROUP

def perf_event_open(attr, pid, cpu, group_fd, 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

PATH_DEBUGFS_TRACING = '/sys/kernel/debug/tracing'
PATH_DEBUGFS_KVM = '/sys/kernel/debug/kvm'

class Group(object):
    def __init__(self):
        self.events = []

    def add_event(self, event):
        self.events.append(event)

    def read(self):
        length = 8 * (1 + len(self.events))
        read_format = 'xxxxxxxx' + 'Q' * len(self.events)
        return dict(zip([event.name for event in self.events],
                        struct.unpack(read_format,
                                      os.read(self.events[0].fd, length))))

class Event(object):
    def __init__(self, name, group, trace_cpu, trace_point, trace_filter,
                 trace_set='kvm'):
        self.name = name
        self.fd = None
        self.setup_event(group, trace_cpu, trace_point, trace_filter,
                         trace_set)

    def setup_event_attribute(self, trace_set, trace_point):
        id_path = os.path.join(PATH_DEBUGFS_TRACING, 'events', trace_set,
                               trace_point, 'id')

        event_attr = perf_event_attr()
        event_attr.config = int(open(id_path).read())
        return event_attr

    def setup_event(self, group, trace_cpu, trace_point, trace_filter,
                    trace_set):
        event_attr = self.setup_event_attribute(trace_set, trace_point)

        group_leader = -1
        if group.events:
            group_leader = group.events[0].fd

        fd = perf_event_open(event_attr, -1, trace_cpu,
                             group_leader, 0)
        if fd == -1:
            err = ctypes.get_errno()
            raise OSError(err, os.strerror(err),
                          'while calling sys_perf_event_open().')

        if trace_filter:
            fcntl.ioctl(fd, ARCH.ioctl_numbers['SET_FILTER'],
                        trace_filter)

        self.fd = fd

    def enable(self):
        fcntl.ioctl(self.fd, ARCH.ioctl_numbers['ENABLE'], 0)

    def disable(self):
        fcntl.ioctl(self.fd, ARCH.ioctl_numbers['DISABLE'], 0)

    def reset(self):
        fcntl.ioctl(self.fd, ARCH.ioctl_numbers['RESET'], 0)

class TracepointProvider(object):
    def __init__(self):
        self.group_leaders = []
        self.filters = get_filters()
        self._fields = self.get_available_fields()
        self.setup_traces()
        self.fields = self._fields

    def get_available_fields(self):
        path = os.path.join(PATH_DEBUGFS_TRACING, 'events', 'kvm')
        fields = walkdir(path)[1]
        extra = []
        for field in fields:
            if field in self.filters:
                filter_name_, filter_dicts = self.filters[field]
                for name in filter_dicts:
                    extra.append(field + '(' + name + ')')
        fields += extra
        return fields

    def setup_traces(self):
        cpus = get_online_cpus()

        # The constant is needed as a buffer for python libs, std
        # streams and other files that the script opens.
        newlim = len(cpus) * len(self._fields) + 50
        try:
            softlim_, hardlim = resource.getrlimit(resource.RLIMIT_NOFILE)

            if hardlim < newlim:
                # Now we need CAP_SYS_RESOURCE, to increase the hard limit.
                resource.setrlimit(resource.RLIMIT_NOFILE, (newlim, newlim))
            else:
                # Raising the soft limit is sufficient.
                resource.setrlimit(resource.RLIMIT_NOFILE, (newlim, hardlim))

        except ValueError:
            sys.exit("NOFILE rlimit could not be raised to {0}".format(newlim))

        for cpu in cpus:
            group = Group()
            for name in self._fields:
                tracepoint = name
                tracefilter = None
                match = re.match(r'(.*)\((.*)\)', name)
                if match:
                    tracepoint, sub = match.groups()
                    tracefilter = ('%s==%d\0' %
                                   (self.filters[tracepoint][0],
                                    self.filters[tracepoint][1][sub]))

                group.add_event(Event(name=name,
                                      group=group,
                                      trace_cpu=cpu,
                                      trace_point=tracepoint,
                                      trace_filter=tracefilter))
            self.group_leaders.append(group)

    def available_fields(self):
        return self.get_available_fields()

    @property
    def fields(self):
        return self._fields

    @fields.setter
    def fields(self, fields):
        self._fields = fields
        for group in self.group_leaders:
            for index, event in enumerate(group.events):
                if event.name in fields:
                    event.reset()
                    event.enable()
                else:
                    # Do not disable the group leader.
                    # It would disable all of its events.
                    if index != 0:
                        event.disable()

    def read(self):
        ret = defaultdict(int)
        for group in self.group_leaders:
            for name, val in group.read().iteritems():
                if name in self._fields:
                    ret[name] += val
        return ret

class DebugfsProvider(object):
    def __init__(self):
        self._fields = self.get_available_fields()

    def get_available_fields(self):
        return walkdir(PATH_DEBUGFS_KVM)[2]

    @property
    def fields(self):
        return self._fields

    @fields.setter
    def fields(self, fields):
        self._fields = fields

    def read(self):
        def val(key):
            return int(file(PATH_DEBUGFS_KVM + '/' + key).read())
        return dict([(key, val(key)) for key in self._fields])

class Stats(object):
    def __init__(self, providers, fields=None):
        self.providers = providers
        self._fields_filter = fields
        self.values = {}
        self.update_provider_filters()

    def update_provider_filters(self):
        def wanted(key):
            if not self._fields_filter:
                return True
            return re.match(self._fields_filter, key) is not None

        # As we reset the counters when updating the fields we can
        # also clear the cache of old values.
        self.values = {}
        for provider in self.providers:
            provider_fields = [key for key in provider.get_available_fields()
                               if wanted(key)]
            provider.fields = provider_fields

    @property
    def fields_filter(self):
        return self._fields_filter

    @fields_filter.setter
    def fields_filter(self, fields_filter):
        self._fields_filter = fields_filter
        self.update_provider_filters()

    def get(self):
        for provider in self.providers:
            new = provider.read()
            for key in provider.fields:
                oldval = self.values.get(key, (0, 0))
                newval = new.get(key, 0)
                newdelta = None
                if oldval is not None:
                    newdelta = newval - oldval[0]
                self.values[key] = (newval, newdelta)
        return self.values

LABEL_WIDTH = 40
NUMBER_WIDTH = 10

class Tui(object):
    def __init__(self, stats):
        self.stats = stats
        self.screen = None
        self.drilldown = False
        self.update_drilldown()

    def __enter__(self):
        """Initialises curses for later use.  Based on curses.wrapper
           implementation from the Python standard library."""
        self.screen = curses.initscr()
        curses.noecho()
        curses.cbreak()

        # The try/catch works around a minor bit of
        # over-conscientiousness in the curses module, the error
        # return from C start_color() is ignorable.
        try:
            curses.start_color()
        except:
            pass

        curses.use_default_colors()
        return self

    def __exit__(self, *exception):
        """Resets the terminal to its normal state.  Based on curses.wrappre
           implementation from the Python standard library."""
        if self.screen:
            self.screen.keypad(0)
            curses.echo()
            curses.nocbreak()
            curses.endwin()

    def update_drilldown(self):
        if not self.stats.fields_filter:
            self.stats.fields_filter = r'^[^\(]*$'

        elif self.stats.fields_filter == r'^[^\(]*$':
            self.stats.fields_filter = None

    def refresh(self, sleeptime):
        self.screen.erase()
        self.screen.addstr(0, 0, 'kvm statistics - summary', curses.A_BOLD)
        self.screen.addstr(2, 1, 'Event')
        self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH -
                           len('Total'), 'Total')
        self.screen.addstr(2, 1 + LABEL_WIDTH + NUMBER_WIDTH + 8 -
                           len('Current'), 'Current')
        row = 3
        stats = self.stats.get()
        def sortkey(x):
            if stats[x][1]:
                return (-stats[x][1], -stats[x][0])
            else:
                return (0, -stats[x][0])
        for key in sorted(stats.keys(), key=sortkey):

            if row >= self.screen.getmaxyx()[0]:
                break
            values = stats[key]
            if not values[0] and not values[1]:
                break
            col = 1
            self.screen.addstr(row, col, key)
            col += LABEL_WIDTH
            self.screen.addstr(row, col, '%10d' % (values[0],))
            col += NUMBER_WIDTH
            if values[1] is not None:
                self.screen.addstr(row, col, '%8d' % (values[1] / sleeptime,))
            row += 1
        self.screen.refresh()

    def show_filter_selection(self):
        while True:
            self.screen.erase()
            self.screen.addstr(0, 0,
                               "Show statistics for events matching a regex.",
                               curses.A_BOLD)
            self.screen.addstr(2, 0,
                               "Current regex: {0}"
                               .format(self.stats.fields_filter))
            self.screen.addstr(3, 0, "New regex: ")
            curses.echo()
            regex = self.screen.getstr()
            curses.noecho()
            if len(regex) == 0:
                return
            try:
                re.compile(regex)
                self.stats.fields_filter = regex
                return
            except re.error:
                continue

    def show_stats(self):
        sleeptime = 0.25
        while True:
            self.refresh(sleeptime)
            curses.halfdelay(int(sleeptime * 10))
            sleeptime = 3
            try:
                char = self.screen.getkey()
                if char == 'x':
                    self.drilldown = not self.drilldown
                    self.update_drilldown()
                if char == 'q':
                    break
                if char == 'f':
                    self.show_filter_selection()
            except KeyboardInterrupt:
                break
            except curses.error:
                continue

def batch(stats):
    s = stats.get()
    time.sleep(1)
    s = stats.get()
    for key in sorted(s.keys()):
        values = s[key]
        print '%-42s%10d%10d' % (key, values[0], values[1])

def log(stats):
    keys = sorted(stats.get().iterkeys())
    def banner():
        for k in keys:
            print '%s' % k,
        print
    def statline():
        s = stats.get()
        for k in keys:
            print ' %9d' % s[k][1],
        print
    line = 0
    banner_repeat = 20
    while True:
        time.sleep(1)
        if line % banner_repeat == 0:
            banner()
        statline()
        line += 1

def get_options():
    description_text = """
This script displays various statistics about VMs running under KVM.
The statistics are gathered from the KVM debugfs entries and / or the
currently available perf traces.

The monitoring takes additional cpu cycles and might affect the VM's
performance.

Requirements:
- Access to:
    /sys/kernel/debug/kvm
    /sys/kernel/debug/trace/events/*
    /proc/pid/task
- /proc/sys/kernel/perf_event_paranoid < 1 if user has no
  CAP_SYS_ADMIN and perf events are used.
- CAP_SYS_RESOURCE if the hard limit is not high enough to allow
  the large number of files that are possibly opened.
"""

    class PlainHelpFormatter(optparse.IndentedHelpFormatter):
        def format_description(self, description):
            if description:
                return description + "\n"
            else:
                return ""

    optparser = optparse.OptionParser(description=description_text,
                                      formatter=PlainHelpFormatter())
    optparser.add_option('-1', '--once', '--batch',
                         action='store_true',
                         default=False,
                         dest='once',
                         help='run in batch mode for one second',
                         )
    optparser.add_option('-l', '--log',
                         action='store_true',
                         default=False,
                         dest='log',
                         help='run in logging mode (like vmstat)',
                         )
    optparser.add_option('-t', '--tracepoints',
                         action='store_true',
                         default=False,
                         dest='tracepoints',
                         help='retrieve statistics from tracepoints',
                         )
    optparser.add_option('-d', '--debugfs',
                         action='store_true',
                         default=False,
                         dest='debugfs',
                         help='retrieve statistics from debugfs',
                         )
    optparser.add_option('-f', '--fields',
                         action='store',
                         default=None,
                         dest='fields',
                         help='fields to display (regex)',
                         )
    (options, _) = optparser.parse_args(sys.argv)
    return options

def get_providers(options):
    providers = []

    if options.tracepoints:
        providers.append(TracepointProvider())
    if options.debugfs:
        providers.append(DebugfsProvider())
    if len(providers) == 0:
        providers.append(TracepointProvider())

    return providers

def check_access(options):
    if not os.path.exists('/sys/kernel/debug'):
        sys.stderr.write('Please enable CONFIG_DEBUG_FS in your kernel.')
        sys.exit(1)

    if not os.path.exists(PATH_DEBUGFS_KVM):
        sys.stderr.write("Please make sure, that debugfs is mounted and "
                         "readable by the current user:\n"
                         "('mount -t debugfs debugfs /sys/kernel/debug')\n"
                         "Also ensure, that the kvm modules are loaded.\n")
        sys.exit(1)

    if not os.path.exists(PATH_DEBUGFS_TRACING) and (options.tracepoints
                                                     or not options.debugfs):
        sys.stderr.write("Please enable CONFIG_TRACING in your kernel "
                         "when using the option -t (default).\n"
                         "If it is enabled, make {0} readable by the "
                         "current user.\n"
                         .format(PATH_DEBUGFS_TRACING))
        if options.tracepoints:
            sys.exit(1)

        sys.stderr.write("Falling back to debugfs statistics!\n")
        options.debugfs = True
        sleep(5)

    return options

def main():
    options = get_options()
    options = check_access(options)
    providers = get_providers(options)
    stats = Stats(providers, fields=options.fields)

    if options.log:
        log(stats)
    elif not options.once:
        with Tui(stats) as tui:
            tui.show_stats()
    else:
        batch(stats)

if __name__ == "__main__":
    main()