Analysis and Utility Functions for Instrumentation
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.
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 function 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
db_term, message or binary.
If one or more carriers could not be scanned in full without harming
the responsiveness of the system,
carrier_info_list() =
{HistogramStart :: integer() >= 0,
Carriers ::
[{AllocatorType :: atom(),
TotalSize :: integer() >= 0,
UnscannedSize :: integer() >= 0,
AllocatedSize :: integer() >= 0,
AllocatedCount :: integer() >= 0,
InPool :: boolean(),
FreeBlocks :: block_histogram()}]}
If the carrier could not be scanned in full without harming the
responsiveness of the system,
Functions
allocations() -> {ok, Result} | {error, Reason}
Result = allocation_summary()Reason = not_enabled
Shorthand for
allocations(#{}).
allocations(Options) -> {ok, Result} | {error, Reason}
Result = allocation_summary()Reason = not_enabledOptions =
#{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, optionally 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_typesThe 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_idsThe scheduler ids whose allocator instances will be searched. A scheduler id of 0 will refer to the global instance that is not tied to any particular scheduler. Defaults to all schedulers and the global instance.
histogram_startThe upper bound of the first interval in the allocated block size histograms. Defaults to 128.
histogram_widthThe number of intervals in the allocated block size histograms. 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}
Result = carrier_info_list()Reason = not_enabled
Shorthand for
carriers(#{}).
carriers(Options) -> {ok, Result} | {error, Reason}
Result = carrier_info_list()Reason = not_enabledOptions =
#{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 filtered 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_typesThe allocator types that will be searched. Defaults to all
alloc_util allocators.
scheduler_idsThe scheduler ids whose allocator instances will be searched. A scheduler id of 0 will refer to the global instance that is not tied to any particular scheduler. Defaults to all schedulers and the global instance.
histogram_startThe upper bound of the first interval in the free block size histograms. Defaults to 512.
histogram_widthThe 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}},
{...}|...]}}