1msacc(3) Erlang Module Definition msacc(3)
2
6 msacc - Convenience functions for microstate accounting
7
9 This module implements some convenience functions for analyzing
10 microstate accounting data. For details about how to use the basic api
11 and what the different states represent see erlang:statis‐
12 tics(microstate_accounting).
13 Basic Scenario
15 1> msacc:start(1000).
17 ok
18 2> msacc:print().
19 Average thread real-time : 1000513 us
20 Accumulated system run-time : 2213 us
21 Average scheduler run-time : 1076 us
22 Thread aux check_io emulator gc other port sleep
24 Stats per thread:
26 async( 0) 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 100.00%
27 async( 1) 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 100.00%
28 aux( 1) 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 99.99%
29 scheduler( 1) 0.00% 0.03% 0.13% 0.00% 0.01% 0.00% 99.82%
30 scheduler( 2) 0.00% 0.00% 0.00% 0.00% 0.03% 0.00% 99.97%
31 Stats per type:
33 async 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 100.00%
34 aux 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 99.99%
35 scheduler 0.00% 0.02% 0.06% 0.00% 0.02% 0.00% 99.89%
36 ok
37 This first command enables microstate accounting for 1000 milliseconds.
40 See start/0, stop/0, reset/0 and start/1 for more details. The second
41 command prints the statistics gathered during that time. First three
42 general statistics are printed.
43 Average real-time:
45 The average time spent collecting data in the threads. This should
46 be close to the time which data was collected.
47 System run-time:
49 The total run-time of all threads in the system. This is what you
50 get if you call msacc:stats(total_runtime,Stats).
51 Average scheduler run-time:
53 The average run-time for the schedulers. This is the average amount
54 of time the schedulers did not sleep.
55 Then one column per state is printed with a the percentage of time this
57 thread spent in the state out of it's own real-time. After the thread
58 specific time, the accumulated time for each type of thread is printed
59 in a similar format.
60 Since we have the average real-time and the percentage spent in each
62 state we can easily calculate the time spent in each state by multiply‐
63 ing Average thread real-time with Thread state %, i.e. to get the time
64 Scheduler 1 spent in the emulator state we do 1000513us * 0.13% =
65 1300us.
66
68 msacc_data() = [msacc_data_thread()]
69 msacc_data_thread() =
71 #{'$type' := msacc_data,
72 type := msacc_type(),
73 id := msacc_id(),
74 counters := msacc_data_counters()}
75 msacc_data_counters() = #{msacc_state() => integer() >= 0}
77 A map containing the different microstate accounting states and
79 the number of microseconds spent in it.
80 msacc_stats() = [msacc_stats_thread()]
82 msacc_stats_thread() =
84 #{'$type' := msacc_stats,
85 type := msacc_type(),
86 id := msacc_id(),
87 system := float(),
88 counters := msacc_stats_counters()}
89 A map containing information about a specific thread. The per‐
91 centages in the map can be either run-time or real-time depend‐
92 ing on if runtime or realtime was requested from stats/2. system
93 is the percentage of total system time for this specific thread.
94 msacc_stats_counters() =
96 #{msacc_state() => #{thread := float(), system := float()}}
97 A map containing the different microstate accounting states.
99 Each value in the map contains another map with the percentage
100 of time that this thread has spent in the specific state. Both
101 the percentage of system time and the time for that specific
102 thread is part of the map.
103 msacc_type() = scheduler | aux | async
105 msacc_id() = integer() >= 0
107 msacc_state() =
109 alloc |
110 aux |
111 bif |
112 busy_wait |
113 check_io |
114 emulator |
115 ets |
116 gc |
117 gc_fullsweep |
118 nif |
119 other |
120 port |
121 send |
122 sleep |
123 timers
124 The different states that a thread can be in. See erlang:sta‐
126 tistics(microstate_accounting) for details.
127 msacc_print_options() = #{system => boolean()}
129 The different options that can be given to print/2.
131
133 available() -> boolean()
134 This function checks whether microstate accounting is available
136 or not.
137 start() -> boolean()
139 Start microstate accounting. Returns whether it was previously
141 enabled or disabled.
142 start(Time) -> true
144 Types:
146 Time = timeout()
148 Resets all counters and then starts microstate accounting for
150 the given milliseconds.
151 stop() -> boolean()
153 Stop microstate accounting. Returns whether is was previously
155 enabled or disabled.
156 reset() -> boolean()
158 Reset microstate accounting counters. Returns whether is was
160 enabled or disabled.
161 print() -> ok
163 Prints the current microstate accounting to standard out. Same
165 as msacc:print(msacc:stats(),#{}).
166 print(DataOrStats) -> ok
168 Types:
170 DataOrStats = msacc_data() | msacc_stats()
172 Print the given microstate statistics values to stdout. Same as
174 msacc:print(DataOrStats,#{}).
175 print(DataOrStats, Options) -> ok
177 Types:
179 DataOrStats = msacc_data() | msacc_stats()
181 Options = msacc_print_options()
182 Print the given microstate statistics values to standard out.
184 With many states this can be quite verbose. See the top of this
185 reference manual for a brief description of what the fields
186 mean.
187 It is possible to print more specific types of statistics by
189 first manipulating the DataOrStats using stats/2. For instance
190 if you want to print the percentage of run-time for each thread
191 you can do:
192 msacc:print(msacc:stats(runtime,msacc:stats())).
194 If you want to only print run-time per thread type you can do:
196 msacc:print(msacc:stats(type,msacc:stats(runtime,msacc:stats()))).
198 Options
200 system:
202 Print percentage of time spent in each state out of system
203 time as well as thread time. Default: false.
204 print(FileOrDevice, DataOrStats, Options) -> ok
206 Types:
208 FileOrDevice = file:filename() | io:device()
210 DataOrStats = msacc_data() | msacc_stats()
211 Options = msacc_print_options()
212 Print the given microstate statistics values to the given file
214 or device. The other arguments behave the same way as for
215 print/2.
216 stats() -> msacc_data()
218 Returns a runtime system independent version of the microstate
220 statistics data presented by erlang:statis‐
221 tics(microstate_accounting). All counters have been normalized
222 to be in microsecond resolution.
223 stats(Analysis, Stats) -> integer() >= 0
225 Types:
227 Analysis = system_realtime | system_runtime
229 Stats = msacc_data()
230 Returns the system time for the given microstate statistics val‐
232 ues. System time is the accumulated time of all threads.
233 realtime:
235 Returns all time recorded for all threads.
236 runtime:
238 Returns all time spent doing work for all threads, i.e. all
239 time not spent in the sleep state.
240 stats(Analysis, Stats) -> msacc_stats()
242 Types:
244 Analysis = realtime | runtime
246 Stats = msacc_data()
247 Returns fractions of real-time or run-time spent in the various
249 threads from the given microstate statistics values.
250 stats(Analysis, StatsOrData) -> msacc_data() | msacc_stats()
252 Types:
254 Analysis = type
256 StatsOrData = msacc_data() | msacc_stats()
257 Returns a list of microstate statistics values where the values
259 for all threads of the same type has been merged.
260 to_file(Filename) -> ok | {error, file:posix()}
262 Types:
264 Filename = file:name_all()
266 Dumps the current microstate statistics counters to a file that
268 can be parsed with file:consult/1.
269 from_file(Filename) -> msacc_data()
271 Types:
273 Filename = file:name_all()
275 Read a file dump produced by to_file(Filename).
277Ericsson AB runtime_tools 1.12.5 msacc(3)