1instrument(3) Erlang Module Definition instrument(3)
2
6 instrument - Analysis and Utility Functions for Instrumentation
7
9 The module instrument contains support for studying the resource usage
10 in an Erlang runtime system. Currently, only the allocation of memory
11 can be studied.
12 Note:
14 Note that this whole module is experimental, and the representations
15 used as well as the functionality is likely to change in the future.
16
19 block_histogram() = tuple()
20 A histogram of block sizes where each interval's upper bound is
22 twice as high as the one before it.
23 The upper bound of the first interval is provided by the func‐
25 tion that returned the histogram, and the last interval has no
26 upper bound.
27 allocation_summary() =
29 {HistogramStart :: integer() >= 0,
30 UnscannedSize :: integer() >= 0,
31 Allocations ::
32 #{Origin :: atom() =>
33 #{Type :: atom() => block_histogram()}}}
34 A summary of allocated block sizes (including their headers)
36 grouped by their Origin and Type.
37 Origin is generally which NIF or driver that allocated the
39 blocks, or 'system' if it could not be determined.
40 Type is the allocation category that the blocks belong to, e.g.
42 db_term, message or binary.
43 If one or more carriers could not be scanned in full without
45 harming the responsiveness of the system, UnscannedSize is the
46 number of bytes that had to be skipped.
47 carrier_info_list() =
49 {HistogramStart :: integer() >= 0,
50 Carriers ::
51 [{AllocatorType :: atom(),
52 TotalSize :: integer() >= 0,
53 UnscannedSize :: integer() >= 0,
54 AllocatedSize :: integer() >= 0,
55 AllocatedCount :: integer() >= 0,
56 InPool :: boolean(),
57 FreeBlocks :: block_histogram()}]}
58 AllocatorType is the type of the allocator that employs this
60 carrier.
61 TotalSize is the total size of the carrier, including its
63 header.
64 AllocatedSize is the combined size of the carrier's allocated
66 blocks, including their headers.
67 AllocatedCount is the number of allocated blocks in the carrier.
69 InPool is whether the carrier is in the migration pool.
71 FreeBlocks is a histogram of the free block sizes in the car‐
73 rier.
74 If the carrier could not be scanned in full without harming the
76 responsiveness of the system, UnscannedSize is the number of
77 bytes that had to be skipped.
78
80 allocations() -> {ok, Result} | {error, Reason}
81 Types:
83 Result = allocation_summary()
85 Reason = not_enabled
86 Shorthand for allocations(#{}).
88 allocations(Options) -> {ok, Result} | {error, Reason}
90 Types:
92 Result = allocation_summary()
94 Reason = not_enabled
95 Options =
96 #{scheduler_ids => [integer() >= 0],
97 allocator_types => [atom()],
98 histogram_start => integer() >= 1,
99 histogram_width => integer() >= 1}
100 Returns a summary of all tagged allocations in the system,
102 optionally filtered by allocator type and scheduler id.
103 Only binaries and allocations made by NIFs and drivers are
105 tagged by default, but this can be configured an a per-allocator
106 basis with the +M<S>atags emulator option.
107 If the specified allocator types are not enabled, the call will
109 fail with {error, not_enabled}.
110 The following options can be used:
112 allocator_types:
114 The allocator types that will be searched. Note that blocks
115 can move freely between allocator types, so restricting the
116 search to certain allocators may return unexpected types
117 (e.g. process heaps when searching binary_alloc), or hide
118 blocks that were migrated out.
119 Defaults to all alloc_util allocators.
121 scheduler_ids:
123 The scheduler ids whose allocator instances will be
124 searched. A scheduler id of 0 will refer to the global
125 instance that is not tied to any particular scheduler.
126 Defaults to all schedulers and the global instance.
127 histogram_start:
129 The upper bound of the first interval in the allocated block
130 size histograms. Defaults to 128.
131 histogram_width:
133 The number of intervals in the allocated block size his‐
134 tograms. Defaults to 18.
135 Example:
137 > instrument:allocations(#{ histogram_start => 128, histogram_width => 15 }).
139 {ok,{128,0,
140 #{udp_inet =>
141 #{driver_event_state => {0,0,0,0,0,0,0,0,0,1,0,0,0,0,0}},
142 system =>
143 #{heap => {0,0,0,0,20,4,2,2,2,3,0,1,0,0,1},
144 db_term => {271,3,1,52,80,1,0,0,0,0,0,0,0,0,0},
145 code => {0,0,0,5,3,6,11,22,19,20,10,2,1,0,0},
146 binary => {18,0,0,0,7,0,0,1,0,0,0,0,0,0,0},
147 message => {0,40,78,2,2,0,0,0,0,0,0,0,0,0,0},
148 ... }
149 spawn_forker =>
150 #{driver_select_data_state =>
151 {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0}},
152 ram_file_drv => #{drv_binary => {0,0,0,0,0,0,1,0,0,0,0,0,0,0,0}},
153 prim_file =>
154 #{process_specific_data => {2,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
155 nif_trap_export_entry => {0,4,0,0,0,0,0,0,0,0,0,0,0,0,0},
156 monitor_extended => {0,1,0,0,0,0,0,0,0,0,0,0,0,0,0},
157 drv_binary => {0,0,0,0,0,0,1,0,3,5,0,0,0,1,0},
158 binary => {0,4,0,0,0,0,0,0,0,0,0,0,0,0,0}},
159 prim_buffer =>
160 #{nif_internal => {0,4,0,0,0,0,0,0,0,0,0,0,0,0,0},
161 binary => {0,4,0,0,0,0,0,0,0,0,0,0,0,0,0}}}}}
162 carriers() -> {ok, Result} | {error, Reason}
165 Types:
167 Result = carrier_info_list()
169 Reason = not_enabled
170 Shorthand for carriers(#{}).
172 carriers(Options) -> {ok, Result} | {error, Reason}
174 Types:
176 Result = carrier_info_list()
178 Reason = not_enabled
179 Options =
180 #{scheduler_ids => [integer() >= 0],
181 allocator_types => [atom()],
182 histogram_start => integer() >= 1,
183 histogram_width => integer() >= 1}
184 Returns a summary of all carriers in the system, optionally fil‐
186 tered by allocator type and scheduler id.
187 If the specified allocator types are not enabled, the call will
189 fail with {error, not_enabled}.
190 The following options can be used:
192 allocator_types:
194 The allocator types that will be searched. Defaults to all
195 alloc_util allocators.
196 scheduler_ids:
198 The scheduler ids whose allocator instances will be
199 searched. A scheduler id of 0 will refer to the global
200 instance that is not tied to any particular scheduler.
201 Defaults to all schedulers and the global instance.
202 histogram_start:
204 The upper bound of the first interval in the free block size
205 histograms. Defaults to 512.
206 histogram_width:
208 The number of intervals in the free block size histograms.
209 Defaults to 14.
210 Example:
212 > instrument:carriers(#{ histogram_start => 512, histogram_width => 8 }).
214 {ok,{512,
215 [{ll_alloc,1048576,0,1048344,71,false,{0,0,0,0,0,0,0,0}},
216 {binary_alloc,1048576,0,324640,13,false,{3,0,0,1,0,0,0,2}},
217 {eheap_alloc,2097152,0,1037200,45,false,{2,1,1,3,4,3,2,2}},
218 {fix_alloc,32768,0,29544,82,false,{22,0,0,0,0,0,0,0}},
219 {...}|...]}}
220
223 erts_alloc(3), erl(1)
224Ericsson AB tools 3.3.1 instrument(3)