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Diffstat (limited to 'src/pmdas/zswap/pmdazswap.python')
| -rw-r--r-- | src/pmdas/zswap/pmdazswap.python | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/src/pmdas/zswap/pmdazswap.python b/src/pmdas/zswap/pmdazswap.python new file mode 100644 index 0000000..ef06d21 --- /dev/null +++ b/src/pmdas/zswap/pmdazswap.python @@ -0,0 +1,189 @@ +''' +Performance Metrics Domain Agent exporting Linux compressed swap metrics. +''' +# +# Copyright (c) 2014 Red Hat. +# +# This program is free software; you can redistribute it and/or modify it +# under the terms of the GNU General Public License as published by the +# Free Software Foundation; either version 2 of the License, or (at your +# option) any later version. +# +# This program is distributed in the hope that it will be useful, but +# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +# for more details. +# + +import cpmapi as c_api +from pcp.pmapi import pmUnits +from pcp.pmda import PMDA, pmdaMetric, pmdaIndom +from resource import getpagesize +from os import getenv, listdir + +ZSWAP_PAGESIZE = getpagesize() +ZSWAP_STATS_PATH = '/sys/kernel/debug/zswap' + +class ZswapPMDA(PMDA): + ''' + Performance Metrics Domain Agent exporting compressed swap metrics. + Install it and make basic use of it if you use zswap, as follows: + + # $PCP_PMDAS_DIR/zswap/Install + $ pminfo -fmdtT zswap + ''' + + def zswap_fetch_single(self, name): + ''' Extract one value from a single zswap statistics file. ''' + fullpath = self.path + '/' + name + try: + with open(fullpath) as file: + value = file.readline() + self.values[name] = long(value) + except: + # use a simple approach to avoiding errors on every fetch + if self.fileerrors < self.nmetrics: + self.err("fetch_single: failed to read %s" % fullpath) + self.fileerrors += 1 + pass + + def zswap_fetch(self): + ''' + Called once per PCP "fetch" PDU from pmcd(1) + Iterates over the (sysfs debug) path holding zswap statistics, + building a hash of values (one value extracted from each file). + ''' + # self.log("fetch: %s" % self.path) + try: + self.patherrors = 0 + files = listdir(self.path) + for name in files: + self.zswap_fetch_single(name) + except: + # the kernel module may simply not be loaded currently + self.patherrors = 1 + pass + + + def zswap_fetch_callback(self, cluster, item, inst): + ''' + Main fetch callback - looks up value associated with requested PMID + (from zswap_fetch), converts units if needed, then returns a list of + value,status (single pair) for the requested pmid + ''' + # self.log("fetch callback for %d.%d[%d]" % (cluster, item, inst)) + if inst != c_api.PM_IN_NULL: + return [c_api.PM_ERR_INST, 0] + elif cluster != 0: + return [c_api.PM_ERR_PMID, 0] + if item >= 0 and item < self.nmetrics and self.patherrors == 1: + return [c_api.PM_ERR_AGAIN, 0] + + if item == 0: + return [self.values['pool_limit_hit'], 1] + elif item == 1: + return [self.values['reject_reclaim_fail'], 1] + elif item == 2: + return [self.values['reject_alloc_fail'], 1] + elif item == 3: + return [self.values['reject_kmemcache_fail'], 1] + elif item == 4: + return [self.values['reject_compress_poor'], 1] + elif item == 5: + return [self.values['written_back_pages'] * self.pagesize, 1] + elif item == 6: + return [self.values['duplicate_entry'], 1] + elif item == 7: + return [self.values['pool_pages'] * self.pagesize, 1] + elif item == 8: + return [self.values['stored_pages'] * self.pagesize, 1] + return [c_api.PM_ERR_PMID, 0] + + + def setup_zswap_metrics(self, name): + ''' + Setup the metric table - ensure a values hash entry is setup for + each metric; that way we don't need to worry about KeyErrors in + the fetch callback routine (e.g. if the kernel interface changes). + ''' + self.values['pool_limit_hit'] = 0 + self.add_metric(name + '.pool_limit_hit', pmdaMetric( + self.pmid(0, 0), + c_api.PM_TYPE_U64, c_api.PM_INDOM_NULL, c_api.PM_SEM_COUNTER, + pmUnits(0, 0, 1, 0, 0, c_api.PM_COUNT_ONE)), + 'Pool limit was hit (see zswap_max_pool_percent module parameter)') + + self.values['reject_reclaim_fail'] = 0 + self.add_metric(name + '.reject_reclaim_fail', pmdaMetric( + self.pmid(0, 1), + c_api.PM_TYPE_U64, c_api.PM_INDOM_NULL, c_api.PM_SEM_COUNTER, + pmUnits(0, 0, 1, 0, 0, c_api.PM_COUNT_ONE)), + 'Store failed due to a reclaim failure after pool limit was reached') + + self.values['reject_alloc_fail'] = 0 + self.add_metric(name + '.reject_alloc_fail', pmdaMetric( + self.pmid(0, 2), + c_api.PM_TYPE_U64, c_api.PM_INDOM_NULL, c_api.PM_SEM_COUNTER, + pmUnits(0, 0, 1, 0, 0, c_api.PM_COUNT_ONE)), + 'Store failed because underlying allocator could not get memory') + + self.values['reject_kmemcache_fail'] = 0 + self.add_metric(name + '.reject_kmemcache_fail', pmdaMetric( + self.pmid(0, 3), + c_api.PM_TYPE_U64, c_api.PM_INDOM_NULL, c_api.PM_SEM_COUNTER, + pmUnits(0, 0, 1, 0, 0, c_api.PM_COUNT_ONE)), + 'Store failed because the entry metadata could not be allocated (rare)') + + self.values['reject_compress_poor'] = 0 + self.add_metric(name + '.reject_compress_poor', pmdaMetric( + self.pmid(0, 4), + c_api.PM_TYPE_U64, c_api.PM_INDOM_NULL, c_api.PM_SEM_COUNTER, + pmUnits(0, 0, 1, 0, 0, c_api.PM_COUNT_ONE)), + 'Compressed page was too big for the allocator to (optimally) store') + + self.values['written_back_pages'] = 0 + self.add_metric(name + '.written_back_pages', pmdaMetric( + self.pmid(0, 5), + c_api.PM_TYPE_U64, c_api.PM_INDOM_NULL, c_api.PM_SEM_COUNTER, + pmUnits(1, 0, 0, c_api.PM_SPACE_KBYTE, 0, 0)), + 'Pages written back when pool limit was reached') + + self.values['duplicate_entry'] = 0 + self.add_metric(name + '.duplicate_entry', pmdaMetric( + self.pmid(0, 6), + c_api.PM_TYPE_U64, c_api.PM_INDOM_NULL, c_api.PM_SEM_COUNTER, + pmUnits(0, 0, 1, 0, 0, c_api.PM_COUNT_ONE)), + 'Duplicate store was encountered (rare)') + + self.values['pool_pages'] = 0 + self.add_metric(name + '.pool_pages', pmdaMetric( + self.pmid(0, 7), + c_api.PM_TYPE_U64, c_api.PM_INDOM_NULL, c_api.PM_SEM_COUNTER, + pmUnits(1, 0, 0, c_api.PM_SPACE_KBYTE, 0, 0)), + 'Memory pages used by the compressed pool') + + self.values['stored_pages'] = 0 + self.add_metric(name + '.stored_pages', pmdaMetric( + self.pmid(0, 8), + c_api.PM_TYPE_U64, c_api.PM_INDOM_NULL, c_api.PM_SEM_COUNTER, + pmUnits(1, 0, 0, c_api.PM_SPACE_KBYTE, 0, 0)), + 'Compressed pages currently stored in zswap') + + + def __init__(self, name, domain): + PMDA.__init__(self, name, domain) + self.patherrors = 0 + self.fileerrors = 0 + self.pagesize = int(getenv('ZSWAP_PAGESIZE', ZSWAP_PAGESIZE)) + self.path = str(getenv('ZSWAP_STATS_PATH', ZSWAP_STATS_PATH)) + + self.values = {} + self.setup_zswap_metrics(name) + self.nmetrics = len(self.values) + + self.set_fetch(self.zswap_fetch) + self.set_fetch_callback(self.zswap_fetch_callback) + + +if __name__ == '__main__': + ZswapPMDA('zswap', 125).run() |