On Fri, Aug 16, 2013 at 05:09:00PM +1200, Andrew Thrift wrote:
> On 8/16/2013 11:35 AM, Darrick J. Wong wrote:
> >Hi all,
> >
> >I wrote a script to dump out various stats about a bcache. It would be nice
> >eventually to put it into bcache-tools so that users don't have to go digging
> >through sysfs, but for now I'm really just wondering, does this program
> >interpret the sysfs files correctly?
> >
> >I'm particularly anxious about 'cache used' since it's just reading out of
> >/sys/fs/bcache/*/cache*/priority_stats and multiplying by cache size...
> >
> >...also I wonder what the negative dirty data count means?
> >
> >$ bcache-status -s
> >--- bcache ---
> >Device /dev/bcache0 (253:0)
> >UUID c4157b48-5cdc-4554-8ce6-520dafdbac55
> >Block Size 4.00KiB
> >Bucket Size 512.00KiB
> >Congested? False
> >Read Congestion 2.0ms
> >Write Congestion 20.0ms
> >Total Cache Size 205.66GiB
> >Total Cache Used 26.74GiB (12%)
> >Total Cache Unused 178.92GiB (87%)
> >Dirty Data 0B (0%)
> >Evictable Cache 205.66GiB (100%)
> >Replacement Policy [lru] fifo random
> >Cache Mode writethrough [writeback] writearound none
> >Total Hits 263809 (56%)
> >Total Misses 199136
> >Total Bypass Hits 9079 (100%)
> >Total Bypass Misses 0
> >Total Bypassed 2.70GiB
> >--- Backing Device ---
> > Device /dev/sdb1 (8:17)
> > Size 698.64GiB
> > Cache Mode writethrough [writeback] writearound none
> > Readahead 0
> > Sequential Cutoff 4.00MiB
> > Merge sequential? True
> > State dirty
> > Writeback? True
> > Dirty Data -2.10MiB
> > Total Hits 263809 (56%)
> > Total Misses 199136
> > Total Bypass Hits 9079 (100%)
> > Total Bypass Misses 0
> > Total Bypassed 2.60GiB
> >--- Cache Device ---
> > Device /dev/sda4 (8:4)
> > Size 205.66GiB
> > Block Size 4.00KiB
> > Bucket Size 512.00KiB
> > Replacement Policy [lru] fifo random
> > Discard? False
> > I/O Errors 0
> > Metadata Written 1.10GiB
> > Data Written 25.30GiB
> > Buckets 421190
> > Cache Used 26.74GiB (12%)
> > Cache Unused 178.92GiB (87%)
> >
> >--D
> >
> >#!/usr/bin/env python3
> ># Dumb script to dump (some) of bcache status
> ># Copyright 2013 Darrick J. Wong. All rights reserved.
> ># This program is licensed under GPLv2.
> >
> >import os
> >import sys
> >
> >MAX_KEY_LENGTH = 28
> >
> >def file_to_lines(fname):
> > try:
> > with open(fname, "r") as fd:
> > return fd.readlines()
> > except:
> > return []
> >
> >def file_to_line(fname):
> > ret = file_to_lines(fname)
> > if len(ret) > 0:
> > return ret[0].strip()
> > return ''
> >
> >def str_to_bool(x):
> > if x == '1':
> > return True
> > return False
> >
> >def format_sectors(x):
> > '''Pretty print a sector count.'''
> > sectors = int(x)
> > asectors = abs(sectors)
> >
> > if asectors == 0:
> > return '0B'
> > elif asectors < 2048:
> > return '%.2fKiB' % (sectors / 2)
> > elif asectors < 2097152:
> > return '%.2fMiB' % (sectors / 2048)
> > elif asectors < 2147483648:
> > return '%.2fGiB' % (sectors / 2097152)
> > else:
> > return '%.2fTiB' % (sectors / 2147483648)
> >
> >def interpret_sectors(x):
> > '''Interpret a pretty-printed disk size.'''
> > factors = {
> > 'k': 1 << 10,
> > 'M': 1 << 20,
> > 'G': 1 << 30,
> > 'T': 1 << 40,
> > 'P': 1 << 50,
> > 'E': 1 << 60,
> > 'Z': 1 << 70,
> > 'Y': 1 << 80,
> > }
> >
> > factor = 1
> > if x[-1] in factors:
> > factor = factors[x[-1]]
> > x = x[:-1]
> > return int(float(x) * factor / 512)
> >
> >def pretty_size(x):
> > return format_sectors(interpret_sectors(x))
> >
> >def dump_bdev(bdev_path):
> > '''Dump a backing device stats.'''
> > global MAX_KEY_LENGTH, devnum_map
> > attrs = [
> > ('../dev', 'Device', lambda x: '%s
> > (%s)' % (devnum_map.get(x, '?'), x)),
> > ('../size', 'Size', format_sectors),
> > ('cache_mode', 'Cache Mode', None),
> > ('readahead', 'Readahead', None),
> > ('sequential_cutoff', 'Sequential Cutoff', pretty_size),
> > ('sequential_merge', 'Merge sequential?', str_to_bool),
> > ('state', 'State', None),
> > ('writeback_running', 'Writeback?', str_to_bool),
> > ('dirty_data', 'Dirty Data', pretty_size),
> > ]
> >
> > print('--- Backing Device ---')
> > for (sysfs_name, display_name, conversion_func) in attrs:
> > val = file_to_line('%s/%s' % (bdev_path, sysfs_name))
> > if conversion_func is not None:
> > val = conversion_func(val)
> > if display_name is None:
> > display_name = sysfs_name
> > print(' %-*s%s' % (MAX_KEY_LENGTH - 2, display_name, val))
> >
> >def dump_cachedev(cachedev_path):
> > '''Dump a cachding device stats.'''
> > def fmt_cachesize(val):
> > return '%s\t(%d%%)' % (format_sectors(val), float(val) /
> > cache_size * 100)
> >
> > global MAX_KEY_LENGTH, devnum_map
> > attrs = [
> > ('../dev', 'Device', lambda
> > x: '%s (%s)' % (devnum_map.get(x, '?'), x)),
> > ('../size', 'Size',
> > format_sectors),
> > ('block_size', 'Block Size',
> > pretty_size),
> > ('bucket_size', 'Bucket Size',
> > pretty_size),
> > ('cache_replacement_policy', 'Replacement Policy', None),
> > ('discard', 'Discard?',
> > str_to_bool),
> > ('io_errors', 'I/O Errors', None),
> > ('metadata_written', 'Metadata Written',
> > pretty_size),
> > ('written', 'Data Written',
> > pretty_size),
> > ('nbuckets', 'Buckets', None),
> > (None, 'Cache Used', lambda
> > x: fmt_cachesize(used_sectors)),
> > (None, 'Cache Unused', lambda
> > x: fmt_cachesize(unused_sectors)),
> > ]
> >
> > stats = get_cache_priority_stats(cachedev_path)
> > cache_size = int(file_to_line('%s/../size' % cachedev_path))
> > unused_sectors = float(stats['Unused'][:-1]) * cache_size / 100
> > used_sectors = cache_size - unused_sectors
> >
> > print('--- Cache Device ---')
> > for (sysfs_name, display_name, conversion_func) in attrs:
> > if sysfs_name is not None:
> > val = file_to_line('%s/%s' % (cachedev_path,
> > sysfs_name))
> > if conversion_func is not None:
> > val = conversion_func(val)
> > if display_name is None:
> > display_name = sysfs_name
> > print(' %-*s%s' % (MAX_KEY_LENGTH - 2, display_name, val))
> >
> >def hits_to_str(hits_str, misses_str):
> > '''Render a hits/misses ratio as a string.'''
> > hits = int(hits_str)
> > misses = int(misses_str)
> >
> > ret = '%d' % hits
> > if hits + misses != 0:
> > ret = '%s\t(%.d%%)' % (ret, 100 * hits / (hits + misses))
> > return ret
> >
> >def dump_stats(sysfs_path, indent_str, stats):
> > '''Dump stats on a bcache device.'''
> > stat_types = [
> > ('five_minute', 'Last 5min'),
> > ('hour', 'Last Hour'),
> > ('day', 'Last Day'),
> > ('total', 'Total'),
> > ]
> > attrs = ['bypassed', 'cache_bypass_hits', 'cache_bypass_misses',
> > 'cache_hits', 'cache_misses']
> > display = [
> > ('Hits', lambda:
> > hits_to_str(stat_data['cache_hits'], stat_data['cache_misses'])),
> > ('Misses', lambda: stat_data['cache_misses']),
> > ('Bypass Hits', lambda:
> > hits_to_str(stat_data['cache_bypass_hits'],
> > stat_data['cache_bypass_misses'])),
> > ('Bypass Misses', lambda:
> > stat_data['cache_bypass_misses']),
> > ('Bypassed', lambda:
> > pretty_size(stat_data['bypassed'])),
> > ]
> >
> > for (sysfs_name, stat_display_name) in stat_types:
> > if len(stats) > 0 and sysfs_name not in stats:
> > continue
> > stat_data = {}
> > for attr in attrs:
> > val = file_to_line('%s/stats_%s/%s' % (sysfs_path,
> > sysfs_name, attr))
> > stat_data[attr] = val
> > for (display_name, str_func) in display:
> > d = '%s%s %s' % (indent_str, stat_display_name,
> > display_name)
> > print('%-*s%s' % (MAX_KEY_LENGTH, d, str_func()))
> >
> >def get_cache_priority_stats(cache):
> > '''Retrieve priority stats from a cache.'''
> > attrs = {}
> >
> > for line in file_to_lines('%s/priority_stats' % cache):
> > x = line.split()
> > key = x[0]
> > value = x[1]
> > attrs[key[:-1]] = value
> > return attrs
> >
> >def dump_bcache(bcache_sysfs_path, stats, print_subdevices, device):
> > '''Dump bcache stats'''
> > global devnum_map
> > def fmt_cachesize(val):
> > return '%s\t(%d%%)' % (format_sectors(val), 100.0 * val /
> > cache_sectors)
> >
> > attrs = [
> > (None, 'Device',
> > lambda x: '%s (%s)' % (devnum_map.get(device, '?'), device)),
> > (None, 'UUID',
> > lambda x: os.path.basename(bcache_sysfs_path)),
> > ('block_size', 'Block Size',
> > pretty_size),
> > ('bucket_size', 'Bucket Size',
> > pretty_size),
> > ('congested', 'Congested?',
> > str_to_bool),
> > ('congested_read_threshold_us', 'Read Congestion',
> > lambda x: '%.1fms' % (int(x) / 1000)),
> > ('congested_write_threshold_us', 'Write Congestion',
> > lambda x: '%.1fms' % (int(x) / 1000)),
> > (None, 'Total Cache Size',
> > lambda x: format_sectors(cache_sectors)),
> > (None, 'Total Cache Used',
> > lambda x: fmt_cachesize(cache_used_sectors)),
> > (None, 'Total Cache Unused',
> > lambda x: fmt_cachesize(cache_unused_sectors)),
> > ('dirty_data', 'Dirty Data',
> > lambda x: fmt_cachesize(interpret_sectors(x))),
> > ('cache_available_percent', 'Evictable Cache',
> > lambda x: '%s\t(%s%%)' % (format_sectors(float(x) * cache_sectors / 100),
> > x)),
> > (None, 'Replacement Policy',
> > lambda x: replacement_policies.pop() if len(replacement_policies) == 1 else
> > '(Unknown)'),
> > (None, 'Cache Mode',
> > lambda x: cache_modes.pop() if len(cache_modes) == 1 else '(Unknown)'),
> > ]
> >
> > # Calculate aggregate data
> > cache_sectors = 0
> > cache_unused_sectors = 0
> > cache_modes = set()
> > replacement_policies = set()
> > for obj in os.listdir(bcache_sysfs_path):
> > if not os.path.isdir('%s/%s' % (bcache_sysfs_path, obj)):
> > continue
> > if obj.startswith('cache'):
> > cache_size = int(file_to_line('%s/%s/../size' %
> > (bcache_sysfs_path, obj)))
> > cache_sectors += cache_size
> > cstats = get_cache_priority_stats('%s/%s' %
> > (bcache_sysfs_path, obj))
> > unused_size = float(cstats['Unused'][:-1]) * cache_size
> > / 100
> > cache_unused_sectors += unused_size
> >
> > replacement_policies.add(file_to_line('%s/%s/cache_replacement_policy' %
> > (bcache_sysfs_path, obj)))
> > elif obj.startswith('bdev'):
> > cache_modes.add(file_to_line('%s/%s/cache_mode' %
> > (bcache_sysfs_path, obj)))
> > cache_used_sectors = cache_sectors - cache_unused_sectors
> >
> > # Dump basic stats
> > print("--- bcache ---")
> > for (sysfs_name, display_name, conversion_func) in attrs:
> > if sysfs_name is not None:
> > val = file_to_line('%s/%s' % (bcache_sysfs_path,
> > sysfs_name))
> > else:
> > val = None
> > if conversion_func is not None:
> > val = conversion_func(val)
> > if display_name is None:
> > display_name = sysfs_name
> > print('%-*s%s' % (MAX_KEY_LENGTH, display_name, val))
> > dump_stats(bcache_sysfs_path, '', stats)
> >
> > # Dump sub-device stats
> > if not print_subdevices:
> > return
> > for obj in os.listdir(bcache_sysfs_path):
> > if not os.path.isdir('%s/%s' % (bcache_sysfs_path, obj)):
> > continue
> > if obj.startswith('bdev'):
> > dump_bdev('%s/%s' % (bcache_sysfs_path, obj))
> > dump_stats('%s/%s' % (bcache_sysfs_path, obj), ' ',
> > stats)
> > elif obj.startswith('cache'):
> > dump_cachedev('%s/%s' % (bcache_sysfs_path, obj))
> >
> >def map_uuid_to_device():
> > '''Map bcache UUIDs to device files.'''
> > global SYSFS_BLOCK_PATH
> > ret = {}
> >
> > for bdev in os.listdir(SYSFS_BLOCK_PATH):
> > link = '%s%s/bcache/cache' % (SYSFS_BLOCK_PATH, bdev)
> > if not os.path.islink(link):
> > continue
> > basename = os.path.basename(os.readlink(link))
> > ret[basename] = file_to_line('%s%s/dev' % (SYSFS_BLOCK_PATH,
> > bdev))
> > return ret
> >
> >def map_devnum_to_device():
> > '''Map device numbers to device files.'''
> > global DEV_BLOCK_PATH
> > ret = {}
> >
> > for bdev in os.listdir(DEV_BLOCK_PATH):
> > ret[bdev] = os.path.realpath('%s%s' % (DEV_BLOCK_PATH, bdev))
> >
> > return ret
> >
> >def print_help():
> > print('Usage: %s [OPTIONS]' % sys.argv[0])
> > print('Options:')
> > print(' -f Print the last five minutes of stats.')
> > print(' -d Print the last hour of stats.')
> > print(' -h Print the last day of stats.')
> > print(' -t Print total stats.')
> > print(' -a Print all stats.')
> > print(' -r Reset stats after printing them.')
> > print(' -s Print subdevice status.')
> > print(' -g Invoke GC before printing status.')
> > print('By default, print only the total stats.')
> >
> >def main():
> > '''Main function'''
> > global SYSFS_BCACHE_PATH
> > global uuid_map, devnum_map
> > stats = set()
> > reset_stats = False
> > print_subdevices = False
> > run_gc = False
> >
> > for arg in sys.argv[1:]:
> > if arg == '--help':
> > print_help()
> > return 0
> > elif arg == '-f':
> > stats.add('five_minute')
> > elif arg == '-h':
> > stats.add('hour')
> > elif arg == '-d':
> > stats.add('day')
> > elif arg == '-t':
> > stats.add('total')
> > elif arg == '-a':
> > stats.add('five_minute')
> > stats.add('hour')
> > stats.add('day')
> > stats.add('total')
> > elif arg == '-r':
> > reset_stats = True
> > elif arg == '-s':
> > print_subdevices = True
> > elif arg == '-g':
> > run_gc = True
> > else:
> > print_help()
> > return 0
> > if len(stats) == 0:
> > stats.add('total')
> >
> > uuid_map = map_uuid_to_device()
> > devnum_map = map_devnum_to_device()
> > for cache in os.listdir(SYSFS_BCACHE_PATH):
> > if not os.path.isdir('%s%s' % (SYSFS_BCACHE_PATH, cache)):
> > continue
> >
> > if run_gc:
> > with open('%s%s/internal/trigger_gc' %
> > (SYSFS_BCACHE_PATH, cache), 'w') as fd:
> > fd.write('1\n')
> >
> > dump_bcache('%s%s' % (SYSFS_BCACHE_PATH, cache), stats,
> > print_subdevices, uuid_map.get(cache, '?'))
> >
> > if reset_stats:
> > with open('%s%s/clear_stats' % (SYSFS_BCACHE_PATH,
> > cache), 'w') as fd:
> > fd.write('1\n')
> >
> >SYSFS_BCACHE_PATH = '/sys/fs/bcache/'
> >SYSFS_BLOCK_PATH = '/sys/block/'
> >DEV_BLOCK_PATH = '/dev/block/'
> >if __name__ == '__main__':
> > main()
> >
> >--
> >To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
> >the body of a message to [email protected]
> >More majordomo info at http://vger.kernel.org/majordomo-info.html
> Hi Darrick,
>
>
> A very useful script indeed.
>
> We made the following changes:
>
> - Removed "Device" from under cache-set header
> - Added "bcache Device" to Backing Device section
> - Changed "Device" to "Physical Device" in Backing Device section
"Device File"? There's nothing requiring the inputs to a cache set be
*physical* devices at all.
> - Removed "Cache Mode" from cache-set header as it set per backing device
I realize that; if all the backing devices have the same cache mode then it'll
print that, otherwise it prints "unknown". Come to think of it, that really
ought to be "various" or something.
> We will make some more changes in the coming weeks to implement a
> brief display mode as well as a verbose display mode.
Cool, thanks. I'm glad you can get some use out of it.
--D
>
> Patch inline:
>
> --- /usr/local/bin/bcache-status 2013-08-16 11:51:55.281095640 +1200
> +++ bcache-status 2013-08-16 17:00:28.884020997 +1200
> @@ -64,11 +64,16 @@
> def pretty_size(x):
> return format_sectors(interpret_sectors(x))
>
> +def device_path(x):
> + x="/dev/block/%s" % x
> + return os.path.abspath(os.path.join(os.path.dirname(x),
> os.readlink(x)))
> +
> def dump_bdev(bdev_path):
> '''Dump a backing device stats.'''
> global MAX_KEY_LENGTH, devnum_map
> attrs = [
> - ('../dev', 'Device', lambda x: '%s
> (%s)' % (devnum_map.get(x, '?'), x)),
> + ('dev/dev', 'bcache Device', device_path),
> + ('../dev', 'Physical Device', lambda x:
> '%s (%s)' % (devnum_map.get(x, '?'), x)),
> ('../size', 'Size', format_sectors),
> ('cache_mode', 'Cache Mode', None),
> ('readahead', 'Readahead', None),
> @@ -180,7 +185,7 @@
> return '%s\t(%d%%)' % (format_sectors(val), 100.0 *
> val / cache_sectors)
>
> attrs = [
> - (None, 'Device', lambda x: '%s (%s)'
> % (devnum_map.get(device, '?'), device)),
> + #(None, 'Device', lambda x: '%s (%s)'
> % (devnum_map.get(device, '?'), device)),
> (None, 'UUID', lambda x:
> os.path.basename(bcache_sysfs_path)),
> ('block_size', 'Block
> Size', pretty_size),
> ('bucket_size', 'Bucket
> Size', pretty_size),
> @@ -268,8 +273,8 @@
> print('Usage: %s [OPTIONS]' % sys.argv[0])
> print('Options:')
> print(' -f Print the last five minutes of stats.')
> - print(' -d Print the last hour of stats.')
> - print(' -h Print the last day of stats.')
> + print(' -h Print the last hour of stats.')
> + print(' -d Print the last day of stats.')
> print(' -t Print total stats.')
> print(' -a Print all stats.')
> print(' -r Reset stats after printing them.')
>
>
> Regards,
>
>
>
>
>
>
>
> Andrew
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