instrument(3erl) Erlang Module Definition instrument(3erl)
NAME
instrument - Analysis and Utility Functions for Instrumentation
DESCRIPTION
The module instrument contains support for studying the resource usage
in an Erlang runtime system. Currently, only the allocation of memory
can be studied.
Note:
Note that this whole module is experimental, and the representations
used as well as the functionality is likely to change in the future.
DATA TYPES
block_histogram() = tuple()
A histogram of block sizes where each interval's upper bound is
twice as high as the one before it.
The upper bound of the first interval is provided by the func-
tion that returned the histogram, and the last interval has no
upper bound.
allocation_summary() =
{HistogramStart :: integer() >= 0,
UnscannedSize :: integer() >= 0,
Allocations ::
#{Origin :: atom() =>
#{Type :: atom() => block_histogram()}}}
A summary of allocated block sizes (including their headers)
grouped by their Origin and Type.
Origin is generally which NIF or driver that allocated the
blocks, or 'system' if it could not be determined.
Type is the allocation category that the blocks belong to, e.g.
db_term, message or binary.
If one or more carriers could not be scanned in full without
harming the responsiveness of the system, UnscannedSize is the
number of bytes that had to be skipped.
carrier_info_list() =
{HistogramStart :: integer() >= 0,
Carriers ::
[{AllocatorType :: atom(),
InPool :: boolean(),
TotalSize :: integer() >= 0,
UnscannedSize :: integer() >= 0,
Allocations ::
{Type :: atom(),
Count :: integer() >= 0,
Size :: integer() >= 0},
FreeBlocks :: block_histogram()}]}
AllocatorType is the type of the allocator that employs this
carrier.
InPool is whether the carrier is in the migration pool.
TotalSize is the total size of the carrier, including its
header.
Allocations is a summary of the allocated blocks in the carrier.
FreeBlocks is a histogram of the free block sizes in the car-
rier.
If the carrier could not be scanned in full without harming the
responsiveness of the system, UnscannedSize is the number of
bytes that had to be skipped.
EXPORTS
allocations() -> {ok, Result} | {error, Reason}
Types:
Result = allocation_summary()
Reason = not_enabled
Shorthand for allocations(#{}).
allocations(Options) -> {ok, Result} | {error, Reason}
Types:
Result = allocation_summary()
Reason = not_enabled
Options =
#{scheduler_ids => [integer() >= 0],
allocator_types => [atom()],
histogram_start => integer() >= 1,
histogram_width => integer() >= 1}
Returns a summary of all tagged allocations in the system, op-
tionally filtered by allocator type and scheduler id.
Only binaries and allocations made by NIFs and drivers are
tagged by default, but this can be configured an a per-allocator
basis with the +M<S>atags emulator option.
If the specified allocator types are not enabled, the call will
fail with {error, not_enabled}.
The following options can be used:
allocator_types:
The allocator types that will be searched. Note that blocks
can move freely between allocator types, so restricting the
search to certain allocators may return unexpected types
(e.g. process heaps when searching binary_alloc), or hide
blocks that were migrated out.
Defaults to all alloc_util allocators.
scheduler_ids:
The scheduler ids whose allocator instances will be
searched. A scheduler id of 0 will refer to the global in-
stance that is not tied to any particular scheduler. De-
faults to all schedulers and the global instance.
histogram_start:
The upper bound of the first interval in the allocated block
size histograms. Defaults to 128.
histogram_width:
The number of intervals in the allocated block size his-
tograms. Defaults to 18.
Example:
> instrument:allocations(#{ histogram_start => 128, histogram_width => 15 }).
{ok,{128,0,
#{udp_inet =>
#{driver_event_state => {0,0,0,0,0,0,0,0,0,1,0,0,0,0,0}},
system =>
#{heap => {0,0,0,0,20,4,2,2,2,3,0,1,0,0,1},
db_term => {271,3,1,52,80,1,0,0,0,0,0,0,0,0,0},
code => {0,0,0,5,3,6,11,22,19,20,10,2,1,0,0},
binary => {18,0,0,0,7,0,0,1,0,0,0,0,0,0,0},
message => {0,40,78,2,2,0,0,0,0,0,0,0,0,0,0},
... }
spawn_forker =>
#{driver_select_data_state =>
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0}},
ram_file_drv => #{drv_binary => {0,0,0,0,0,0,1,0,0,0,0,0,0,0,0}},
prim_file =>
#{process_specific_data => {2,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
nif_trap_export_entry => {0,4,0,0,0,0,0,0,0,0,0,0,0,0,0},
monitor_extended => {0,1,0,0,0,0,0,0,0,0,0,0,0,0,0},
drv_binary => {0,0,0,0,0,0,1,0,3,5,0,0,0,1,0},
binary => {0,4,0,0,0,0,0,0,0,0,0,0,0,0,0}},
prim_buffer =>
#{nif_internal => {0,4,0,0,0,0,0,0,0,0,0,0,0,0,0},
binary => {0,4,0,0,0,0,0,0,0,0,0,0,0,0,0}}}}}
carriers() -> {ok, Result} | {error, Reason}
Types:
Result = carrier_info_list()
Reason = not_enabled
Shorthand for carriers(#{}).
carriers(Options) -> {ok, Result} | {error, Reason}
Types:
Result = carrier_info_list()
Reason = not_enabled
Options =
#{scheduler_ids => [integer() >= 0],
allocator_types => [atom()],
histogram_start => integer() >= 1,
histogram_width => integer() >= 1}
Returns a summary of all carriers in the system, optionally fil-
tered by allocator type and scheduler id.
If the specified allocator types are not enabled, the call will
fail with {error, not_enabled}.
The following options can be used:
allocator_types:
The allocator types that will be searched. Defaults to all
alloc_util allocators.
scheduler_ids:
The scheduler ids whose allocator instances will be
searched. A scheduler id of 0 will refer to the global in-
stance that is not tied to any particular scheduler. De-
faults to all schedulers and the global instance.
histogram_start:
The upper bound of the first interval in the free block size
histograms. Defaults to 512.
histogram_width:
The number of intervals in the free block size histograms.
Defaults to 14.
Example:
> instrument:carriers(#{ histogram_start => 512, histogram_width => 8 }).
{ok,{512,
[{ll_alloc,1048576,0,1048344,71,false,{0,0,0,0,0,0,0,0}},
{binary_alloc,1048576,0,324640,13,false,{3,0,0,1,0,0,0,2}},
{eheap_alloc,2097152,0,1037200,45,false,{2,1,1,3,4,3,2,2}},
{fix_alloc,32768,0,29544,82,false,{22,0,0,0,0,0,0,0}},
{...}|...]}}
SEE ALSO
erts_alloc(3erl), erl(1)
Ericsson AB tools 3.4 instrument(3erl)