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Diffstat (limited to 'lib/kernel/src/logger_h_common.hrl')
| -rw-r--r-- | lib/kernel/src/logger_h_common.hrl | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/lib/kernel/src/logger_h_common.hrl b/lib/kernel/src/logger_h_common.hrl new file mode 100644 index 0000000000..f110bbaf97 --- /dev/null +++ b/lib/kernel/src/logger_h_common.hrl @@ -0,0 +1,262 @@ + +%%%----------------------------------------------------------------- +%%% Overload protection configuration + +%%! *** NOTE *** +%%! It's important that: +%%! TOGGLE_SYNC_QLEN < DROP_NEW_REQS_QLEN < FLUSH_REQS_QLEN +%%! and that DROP_NEW_REQS_QLEN >= 2. +%%! Otherwise the handler could end up in drop mode with no new +%%! log requests to process. This would cause all future requests +%%! to be dropped (no switch to async mode would ever take place). + +%% This specifies the message_queue_len value where the log +%% requests switch from asynchronous casts to synchronous calls. +-define(TOGGLE_SYNC_QLEN, 10). +%% Above this message_queue_len, log requests will be dropped, +%% i.e. no log requests get sent to the handler process. +-define(DROP_NEW_REQS_QLEN, 200). +%% Above this message_queue_len, the handler process will flush +%% its mailbox and only leave this number of messages in it. +-define(FLUSH_REQS_QLEN, 1000). + +%% Never flush more than this number of messages in one go, +%% or the handler will be unresponsive for seconds (keep this +%% number as large as possible or the mailbox could grow large). +-define(FLUSH_MAX_N, 5000). + +%% BURST_LIMIT is the max number of log requests allowed to be +%% written within a BURST_WINDOW_TIME time frame. +-define(ENABLE_BURST_LIMIT, true). +-define(BURST_LIMIT_SIZE, 500). +-define(BURST_WINDOW_TIME, 1000). + +%% This enables/disables the feature to automatically get the +%% handler terminated if it gets too loaded (and can't keep up). +-define(ENABLE_KILL_OVERLOADED, false). +%% If the message_queue_len goes above this size even after +%% flushing has been performed, the handler is terminated. +-define(HANDLER_OVERLOADED_QLEN, 20000). +%% If the memory usage exceeds this level +-define(HANDLER_OVERLOADED_MEM, 3000000). + +%% This is the default time that the handler will wait before +%% restarting and accepting new requests. The value 'never' +%% disables restarts. +-define(HANDLER_RESTART_AFTER, 5000). +%%-define(HANDLER_RESTART_AFTER, never). + +%% The handler sends asynchronous write requests to the process +%% controlling the i/o device, but every once in this interval +%% will the write request be synchronous, so that the i/o device +%% process doesn't get overloaded. This gives the handler time +%% to keep up with its mailbox in overload situations, even if +%% the i/o is slow. +-define(CONTROLLER_SYNC_INTERVAL, 20). +%% The handler will not perform a file sync operation if the +%% mailbox size is greater than this number. This is to ensure +%% the handler process doesn't get overloaded while waiting for +%% an expensive file sync operation to finish. +-define(FILESYNC_OK_QLEN, 2). +%% Do a file/disk_log sync operation every integer() millisec +%% (if necessary) or set to 'no_repeat' to only do file sync when +%% the handler is idle. Note that file sync is not guaranteed to +%% happen automatically if this operation is disabled. +-define(FILESYNC_REPEAT_INTERVAL, 5000). +%%-define(FILESYNC_REPEAT_INTERVAL, no_repeat). + +%% This is the time after last message received that we think/hope +%% that the handler has an empty mailbox (no new log request has +%% come in). +-define(IDLE_DETECT_TIME_MSEC, 100). +-define(IDLE_DETECT_TIME_USEC, 100000). + +%% Default disk log option values +-define(DISK_LOG_TYPE, wrap). +-define(DISK_LOG_MAX_NO_FILES, 10). +-define(DISK_LOG_MAX_NO_BYTES, 1048576). + +%%%----------------------------------------------------------------- +%%% Overload protection macros + +-define(timestamp(), erlang:monotonic_time(microsecond)). + +-define(get_mode(HandlerName), + case ets:lookup(HandlerName, mode) of + [{mode,sync}] -> + case whereis(HandlerName)==self() of + true -> async; + _ -> sync + end; + [{mode,M}] -> M; + _ -> async + end). + +-define(set_mode(HandlerName, M), + begin ets:insert(HandlerName, {mode,M}), M end). + +-define(change_mode(HandlerName, M0, M1), + if M0 == M1 -> + M0; + true -> + ets:insert(HandlerName, {mode,M1}), + M1 + end). + +-define(min(X1, X2), + if X2 == undefined -> X1; + X2 < X1 -> X2; + true -> X1 + end). + +-define(max(X1, X2), + if + X2 == undefined -> X1; + X2 > X1 -> X2; + true -> X1 + end). + +-define(diff_time(OS_T1, OS_T0), OS_T1-OS_T0). + +%%%----------------------------------------------------------------- +%%% The test hook macros make it possible to observe and manipulate +%%% internal handler functionality. When enabled, these macros will +%%% slow down execution and therefore should not be include in code +%%% to be officially released. + +%% -define(TEST_HOOKS, true). +-ifdef(TEST_HOOKS). + -define(TEST_HOOKS_TAB, logger_h_test_hooks). + + -define(init_test_hooks(), + _ = case ets:whereis(?TEST_HOOKS_TAB) of + undefined -> ets:new(?TEST_HOOKS_TAB, [named_table,public]); + _ -> ok + end, + ets:insert(?TEST_HOOKS_TAB, {internal_log,{logger,internal_log}}), + ets:insert(?TEST_HOOKS_TAB, {file_write,ok}), + ets:insert(?TEST_HOOKS_TAB, {file_datasync,ok}), + ets:insert(?TEST_HOOKS_TAB, {disk_log_blog,ok}), + ets:insert(?TEST_HOOKS_TAB, {disk_log_sync,ok})). + + -define(set_internal_log(MOD_FUNC), + ets:insert(?TEST_HOOKS_TAB, {internal_log,MOD_FUNC})). + + -define(set_result(OPERATION, RESULT), + ets:insert(?TEST_HOOKS_TAB, {OPERATION,RESULT})). + + -define(set_defaults(), + ets:insert(?TEST_HOOKS_TAB, {internal_log,{logger,internal_log}}), + ets:insert(?TEST_HOOKS_TAB, {file_write,ok}), + ets:insert(?TEST_HOOKS_TAB, {file_datasync,ok}), + ets:insert(?TEST_HOOKS_TAB, {disk_log_blog,ok}), + ets:insert(?TEST_HOOKS_TAB, {disk_log_sync,ok})). + + -define(internal_log(TYPE, TERM), + try ets:lookup(?TEST_HOOKS_TAB, internal_log) of + [{_,{LMOD,LFUNC}}] -> apply(LMOD, LFUNC, [TYPE,TERM]); + _ -> logger:internal_log(TYPE, TERM) + catch _:_ -> logger:internal_log(TYPE, TERM) end). + + -define(file_write(DEVICE, DATA), + try ets:lookup(?TEST_HOOKS_TAB, file_write) of + [{_,ok}] -> file:write(DEVICE, DATA); + [{_,ERROR}] -> ERROR + catch _:_ -> file:write(DEVICE, DATA) end). + + -define(file_datasync(DEVICE), + try ets:lookup(?TEST_HOOKS_TAB, file_datasync) of + [{_,ok}] -> file:datasync(DEVICE); + [{_,ERROR}] -> ERROR + catch _:_ -> file:datasync(DEVICE) end). + + -define(disk_log_blog(LOG, DATA), + try ets:lookup(?TEST_HOOKS_TAB, disk_log_blog) of + [{_,ok}] -> disk_log:blog(LOG, DATA); + [{_,ERROR}] -> ERROR + catch _:_ -> disk_log:blog(LOG, DATA) end). + + -define(disk_log_sync(LOG), + try ets:lookup(?TEST_HOOKS_TAB, disk_log_sync) of + [{_,ok}] -> disk_log:sync(LOG); + [{_,ERROR}] -> ERROR + catch _:_ -> disk_log:sync(LOG) end). + + -define(DEFAULT_CALL_TIMEOUT, 5000). + +-else. % DEFAULTS! + -define(TEST_HOOKS_TAB, undefined). + -define(init_test_hooks(), ok). + -define(set_internal_log(_MOD_FUNC), ok). + -define(set_result(_OPERATION, _RESULT), ok). + -define(set_defaults(), ok). + -define(internal_log(TYPE, TERM), logger:internal_log(TYPE, TERM)). + -define(file_write(DEVICE, DATA), file:write(DEVICE, DATA)). + -define(file_datasync(DEVICE), file:datasync(DEVICE)). + -define(disk_log_blog(LOG, DATA), disk_log:blog(LOG, DATA)). + -define(disk_log_sync(LOG), disk_log:sync(LOG)). + -define(DEFAULT_CALL_TIMEOUT, ?DEFAULT_LOGGER_CALL_TIMEOUT-2000). +-endif. + +%%%----------------------------------------------------------------- +%%% These macros enable statistics counters in the state of the +%%% handler which is useful for analysing the overload protection +%%% behaviour. These counters should not be included in code to be +%%% officially released (as some counters will grow very large +%%% over time). + +%%-define(SAVE_STATS, true). +-ifdef(SAVE_STATS). + -define(merge_with_stats(STATE), + STATE#{flushes => 0, flushed => 0, drops => 0, + casts => 0, calls => 0, + max_qlen => 0, max_time => 0}). + + -define(update_max_qlen(QLEN, STATE), + begin #{max_qlen := QLEN0} = STATE, + STATE#{max_qlen => ?max(QLEN0,QLEN)} end). + + -define(update_calls_or_casts(CALL_OR_CAST, INC, STATE), + case CALL_OR_CAST of + cast -> + #{casts := CASTS0} = STATE, + STATE#{casts => CASTS0+INC}; + call -> + #{calls := CALLS0} = STATE, + STATE#{calls => CALLS0+INC} + end). + + -define(update_max_time(TIME, STATE), + begin #{max_time := TIME0} = STATE, + STATE#{max_time => ?max(TIME0,TIME)} end). + + -define(update_other(OTHER, VAR, INCVAL, STATE), + begin #{OTHER := VAR} = STATE, + STATE#{OTHER => VAR+INCVAL} end). + +-else. % DEFAULT! + -define(merge_with_stats(STATE), STATE). + -define(update_max_qlen(_QLEN, STATE), STATE). + -define(update_calls_or_casts(_CALL_OR_CAST, _INC, STATE), STATE). + -define(update_max_time(_TIME, STATE), STATE). + -define(update_other(_OTHER, _VAR, _INCVAL, STATE), STATE). +-endif. + +%%%----------------------------------------------------------------- +%%% These macros enable callbacks that make it possible to analyse +%%% the overload protection behaviour from outside the handler +%%% process (including dropped requests on the client side). +%%% An external callback module (?OBSERVER_MOD) is required which +%%% is not part of the kernel application. For this reason, these +%%% callbacks should not be included in code to be officially released. + +%%-define(OBSERVER_MOD, logger_test). +-ifdef(OBSERVER_MOD). + -define(start_observation(NAME), ?OBSERVER:start_observation(NAME)). + -define(observe(NAME,EVENT), ?OBSERVER:observe(NAME,EVENT)). + +-else. % DEFAULT! + -define(start_observation(_NAME), ok). + -define(observe(_NAME,_EVENT), ok). +-endif. +%%! <--- |