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* rrdset - in progress * rrdset optimal constructor; rrdset conflict * rrdset final touches * re-organization of rrdset object members * prevent use-after-free * dictionary dfe supports also counting of iterations * rrddim managed by dictionary * rrd.h cleanup * DICTIONARY_ITEM now is referencing actual dictionary items in the code * removed rrdset linked list * Revert "removed rrdset linked list" This reverts commit 690d6a588b4b99619c2c5e10f84e8f868ae6def5. * removed rrdset linked list * added comments * Switch chart uuid to static allocation in rrdset Remove unused functions * rrdset_archive() and friends... * always create rrdfamily * enable ml_free_dimension * rrddim_foreach done with dfe * most custom rrddim loops replaced with rrddim_foreach * removed accesses to rrddim->dimensions * removed locks that are no longer needed * rrdsetvar is now managed by the dictionary * set rrdset is rrdsetvar, fixes https://github.com/netdata/netdata/pull/13646#issuecomment-1242574853 * conflict callback of rrdsetvar now properly checks if it has to reset the variable * dictionary registered callbacks accept as first parameter the DICTIONARY_ITEM * dictionary dfe now uses internal counter to report; avoided excess variables defined with dfe * dictionary walkthrough callbacks get dictionary acquired items * dictionary reference counters that can be dupped from zero * added advanced functions for get and del * rrdvar managed by dictionaries * thread safety for rrdsetvar * faster rrdvar initialization * rrdvar string lengths should match in all add, del, get functions * rrdvar internals hidden from the rest of the world * rrdvar is now acquired throughout netdata * hide the internal structures of rrdsetvar * rrdsetvar is now acquired through out netdata * rrddimvar managed by dictionary; rrddimvar linked list removed; rrddimvar structures hidden from the rest of netdata * better error handling * dont create variables if not initialized for health * dont create variables if not initialized for health again * rrdfamily is now managed by dictionaries; references of it are acquired dictionary items * type checking on acquired objects * rrdcalc renaming of functions * type checking for rrdfamily_acquired * rrdcalc managed by dictionaries * rrdcalc double free fix * host rrdvars is always needed * attempt to fix deadlock 1 * attempt to fix deadlock 2 * Remove unused variable * attempt to fix deadlock 3 * snprintfz * rrdcalc index in rrdset fix * Stop storing active charts and computing chart hashes * Remove store active chart function * Remove compute chart hash function * Remove sql_store_chart_hash function * Remove store_active_dimension function * dictionary delayed destruction * formatting and cleanup * zero dictionary base on rrdsetvar * added internal error to log delayed destructions of dictionaries * typo in rrddimvar * added debugging info to dictionary * debug info * fix for rrdcalc keys being empty * remove forgotten unlock * remove deadlock * Switch to metadata version 5 and drop chart_hash chart_hash_map chart_active dimension_active v_chart_hash * SQL cosmetic changes * do not busy wait while destroying a referenced dictionary * remove deadlock * code cleanup; re-organization; * fast cleanup and flushing of dictionaries * number formatting fixes * do not delete configured alerts when archiving a chart * rrddim obsolete linked list management outside dictionaries * removed duplicate contexts call * fix crash when rrdfamily is not initialized * dont keep rrddimvar referenced * properly cleanup rrdvar * removed some locks * Do not attempt to cleanup chart_hash / chart_hash_map * rrdcalctemplate managed by dictionary * register callbacks on the right dictionary * removed some more locks * rrdcalc secondary index replaced with linked-list; rrdcalc labels updates are now executed by health thread * when looking up for an alarm look using both chart id and chart name * host initialization a bit more modular * init rrdlabels on host update * preparation for dictionary views * improved comment * unused variables without internal checks * service threads isolation and worker info * more worker info in service thread * thread cancelability debugging with internal checks * strings data races addressed; fixes https://github.com/netdata/netdata/issues/13647 * dictionary modularization * Remove unused SQL statement definition * unit-tested thread safety of dictionaries; removed data race conditions on dictionaries and strings; dictionaries now can detect if the caller is holds a write lock and automatically all the calls become their unsafe versions; all direct calls to unsafe version is eliminated * remove worker_is_idle() from the exit of service functions, because we lose the lock time between loops * rewritten dictionary to have 2 separate locks, one for indexing and another for traversal * Update collectors/cgroups.plugin/sys_fs_cgroup.c Co-authored-by: Vladimir Kobal <vlad@prokk.net> * Update collectors/cgroups.plugin/sys_fs_cgroup.c Co-authored-by: Vladimir Kobal <vlad@prokk.net> * Update collectors/proc.plugin/proc_net_dev.c Co-authored-by: Vladimir Kobal <vlad@prokk.net> * fix memory leak in rrdset cache_dir * minor dictionary changes * dont use index locks in single threaded * obsolete dict option * rrddim options and flags separation; rrdset_done() optimization to keep array of reference pointers to rrddim; * fix jump on uninitialized value in dictionary; remove double free of cache_dir * addressed codacy findings * removed debugging code * use the private refcount on dictionaries * make dictionary item desctructors work on dictionary destruction; strictier control on dictionary API; proper cleanup sequence on rrddim; * more dictionary statistics * global statistics about dictionary operations, memory, items, callbacks * dictionary support for views - missing the public API * removed warning about unused parameter * chart and context name for cloud * chart and context name for cloud, again * dictionary statistics fixed; first implementation of dictionary views - not currently used * only the master can globally delete an item * context needs netdata prefix * fix context and chart it of spins * fix for host variables when health is not enabled * run garbage collector on item insert too * Fix info message; remove extra "using" * update dict unittest for new placement of garbage collector * we need RRDHOST->rrdvars for maintaining custom host variables * Health initialization needs the host->host_uuid * split STRING to its own files; no code changes other than that * initialize health unconditionally * unit tests do not pollute the global scope with their variables * Skip initialization when creating archived hosts on startup. When a child connects it will initialize properly Co-authored-by: Stelios Fragkakis <52996999+stelfrag@users.noreply.github.com> Co-authored-by: Vladimir Kobal <vlad@prokk.net>
5.6 KiB
5.6 KiB
How to trace netdata locks
To enable tracing rwlocks in netdata, compile netdata by setting CFLAGS="-DNETDATA_TRACE_RWLOCKS=1", like this:
CFLAGS="-O1 -ggdb -DNETDATA_TRACE_RWLOCKS=1" ./netdata-installer.sh
During compilation, the compiler will log:
libnetdata/locks/locks.c:105:2: warning: #warning NETDATA_TRACE_RWLOCKS ENABLED - EXPECT A LOT OF OUTPUT [-Wcpp]
105 | #warning NETDATA_TRACE_RWLOCKS ENABLED - EXPECT A LOT OF OUTPUT
| ^~~~~~~
Once compiled, netdata will do the following:
Every call to netdata_rwlock_*() is now measured in time.
logging of slow locks/unlocks
If any call takes more than 10 usec, it will be logged like this:
RW_LOCK ON LOCK 0x0x7fbe1f2e5190: 4157038, 'ACLK_Query_2' (function build_context_param_list() 99@web/api/formatters/rrd2json.c) WAITED to UNLOCK for 29 usec.
The time can be changed by setting this -DNETDATA_TRACE_RWLOCKS_WAIT_TIME_TO_IGNORE_USEC=20 (or whatever number) to the CFLAGS.
logging of long hold times
If any lock is holded for more than 10000 usec, it will be logged like this:
RW_LOCK ON LOCK 0x0x55a20afc1b20: 4187198, 'ANALYTICS' (function analytics_gather_mutable_meta_data() 532@daemon/analytics.c) holded a 'R' for 13232 usec.
The time can be changed by setting this -DNETDATA_TRACE_RWLOCKS_HOLD_TIME_TO_IGNORE_USEC=20000 (or whatever number) to the CFLAGS.
logging for probable pauses (predictive)
The library maintains a linked-list of all the lock holders (one entry per thread). For this linked-list a mutex is used. So every call to the r/w locks now also has a mutex lock.
If any call is expected to pause the caller (ie the caller is attempting a read lock while there is a write lock in place and vice versa), the library will log something like this:
RW_LOCK ON LOCK 0x0x5651c9fcce20: 4190039 'HEALTH' (function health_execute_pending_updates() 661@health/health.c) WANTS a 'W' lock (while holding 1 rwlocks and 1 mutexes).
There are 7 readers and 0 writers are holding the lock:
=> 1: RW_LOCK: process 4190091 'WEB_SERVER[static14]' (function web_client_api_request_v1_data() 526@web/api/web_api_v1.c) is having 1 'R' lock for 709847 usec.
=> 2: RW_LOCK: process 4190079 'WEB_SERVER[static6]' (function web_client_api_request_v1_data() 526@web/api/web_api_v1.c) is having 1 'R' lock for 709869 usec.
=> 3: RW_LOCK: process 4190084 'WEB_SERVER[static10]' (function web_client_api_request_v1_data() 526@web/api/web_api_v1.c) is having 1 'R' lock for 709948 usec.
=> 4: RW_LOCK: process 4190076 'WEB_SERVER[static3]' (function web_client_api_request_v1_data() 526@web/api/web_api_v1.c) is having 1 'R' lock for 710190 usec.
=> 5: RW_LOCK: process 4190092 'WEB_SERVER[static15]' (function web_client_api_request_v1_data() 526@web/api/web_api_v1.c) is having 1 'R' lock for 710195 usec.
=> 6: RW_LOCK: process 4190077 'WEB_SERVER[static4]' (function web_client_api_request_v1_data() 526@web/api/web_api_v1.c) is having 1 'R' lock for 710208 usec.
=> 7: RW_LOCK: process 4190044 'WEB_SERVER[static1]' (function web_client_api_request_v1_data() 526@web/api/web_api_v1.c) is having 1 'R' lock for 710221 usec.
And each of the above is paired with a GOT log, like this:
RW_LOCK ON LOCK 0x0x5651c9fcce20: 4190039 'HEALTH' (function health_execute_pending_updates() 661@health/health.c) GOT a 'W' lock (while holding 2 rwlocks and 1 mutexes).
There are 0 readers and 1 writers are holding the lock:
=> 1: RW_LOCK: process 4190039 'HEALTH' (function health_execute_pending_updates() 661@health/health.c) is having 1 'W' lock for 36 usec.
Keep in mind that the lock and log are not atomic. The list of callers is indicative (and sometimes just empty because the original holders of the lock, unlocked it until we had the chance to print their names).
POSIX compliance check
The library may also log messages about POSIX unsupported cases, like this:
RW_LOCK FATAL ON LOCK 0x0x622000109290: 3609368 'PLUGIN[proc]' (function __rrdset_check_rdlock() 10@database/rrdset.c) attempts to acquire a 'W' lock.
But it is not supported by POSIX because: ALREADY HAS THIS LOCK
At this attempt, the task is holding 1 rwlocks and 1 mutexes.
There are 1 readers and 0 writers are holding the lock requested now:
=> 1: RW_LOCK: process 3609368 'PLUGIN[proc]' (function rrdset_done() 1398@database/rrdset.c) is having 1 'R' lock for 0 usec.
nested read locks
When compiled with -DNETDATA_TRACE_RWLOCKS_LOG_NESTED=1 the library will also detect nested read locks and print them like this:
RW_LOCK ON LOCK 0x0x7ff6ea46d190: 4140225 'WEB_SERVER[static14]' (function rrdr_json_wrapper_begin() 34@web/api/formatters/json_wrapper.c) NESTED READ LOCK REQUEST a 'R' lock (while holding 1 rwlocks and 1 mutexes).
There are 5 readers and 0 writers are holding the lock:
=> 1: RW_LOCK: process 4140225 'WEB_SERVER[static14]' (function rrdr_lock_rrdset() 70@web/api/queries/rrdr.c) is having 1 'R' lock for 216667 usec.
=> 2: RW_LOCK: process 4140211 'WEB_SERVER[static6]' (function rrdr_lock_rrdset() 70@web/api/queries/rrdr.c) is having 1 'R' lock for 220001 usec.
=> 3: RW_LOCK: process 4140218 'WEB_SERVER[static8]' (function rrdr_lock_rrdset() 70@web/api/queries/rrdr.c) is having 1 'R' lock for 220001 usec.
=> 4: RW_LOCK: process 4140224 'WEB_SERVER[static13]' (function rrdr_lock_rrdset() 70@web/api/queries/rrdr.c) is having 1 'R' lock for 220001 usec.
=> 5: RW_LOCK: process 4140227 'WEB_SERVER[static16]' (function rrdr_lock_rrdset() 70@web/api/queries/rrdr.c) is having 1 'R' lock for 220001 usec.