unikernel/duniverse/dune_/bench/metrics.mli

@@ -0,0 +1,66 @@
+open Stdune
+
+(** [('float, 'int) t] is a record of metrics about the current process. It
+    includes timing information and information available from [Gc.stat]. It is
+    polymorphic in the type of field values to allow for the definition of
+    [unzip] functions which make serialisation easier. *)
+type ('float, 'int) t =
+  { elapsed_time : 'float
+    (** Real time elapsed since the process started and the process
+      finished. *)
+  ; user_cpu_time : 'float
+    (** The amount of CPU time spent in user mode during the process. Other
+      processes and blocked time are not included. *)
+  ; system_cpu_time : 'float
+    (** The amount of CPU time spent in kernel mode during the process.
+      Similar to user time, other processes and time spent blocked by
+      other processes are not counted. *)
+  ; minor_words : 'float
+    (** Number of words allocated in the minor heap since the program was
+      started. *)
+  ; promoted_words : 'float
+    (** Number of words that have been promoted from the minor to the major
+      heap since the program was started. *)
+  ; major_words : 'float
+    (** Number of words allocated in the major heap since the program was
+      started. *)
+  ; minor_collections : 'int
+    (** Number of minor collections since the program was started. *)
+  ; major_collections : 'int
+    (** Number of major collection cycles completed since the program was
+      started. *)
+  ; heap_words : 'int (** Total size of the major heap, in words. *)
+  ; heap_chunks : 'int
+    (** Number of contiguous pieces of memory that make up the major heap. *)
+  ; live_words : 'int
+    (** Number of words of live data in the major heap, including the header
+      words. *)
+  ; live_blocks : 'int (** Number of live blocks in the major heap. *)
+  ; free_words : 'int (** Number of words in the free list. *)
+  ; free_blocks : 'int (** Number of blocks in the free list. *)
+  ; largest_free : 'int (** Size (in words) of the largest block in the free list. *)
+  ; fragments : 'int
+    (** Number of wasted words due to fragmentation. These are 1-words free
+      blocks placed between two live blocks. They are not available for
+      allocation. *)
+  ; compactions : 'int (** Number of heap compactions since the program was started. *)
+  ; top_heap_words : 'int (** Maximum size reached by the major heap, in words. *)
+  ; stack_size : 'int (** Current size of the stack, in words. *)
+  }
+
+(** [make t gc] creates a new metrics record from the given [t] and [gc]
+    information. *)
+val make : Proc.Times.t -> Gc.stat -> (float, int) t
+
+(** [map ~f ~g m] applies [f] to the float fields and [g] to the int fields of
+    [m]. *)
+val map
+  :  f:('float -> 'float_)
+  -> g:('int -> 'int_)
+  -> ('float, 'int) t
+  -> ('float_, 'int_) t
+
+(** [unzip m] takes a list of metrics [m] and returns a records with the lists
+    of values for each field. This is particularly convenient when serialising
+    to json. *)
+val unzip : ('float, 'int) t list -> ('float list, 'int list) t