Make Profile.init more flexible (fix #7365)

base/profile.jl

@@ -21,6 +21,17 @@ end
 ####
 #### User-level functions
 ####
+function init(; n::Union(Nothing,Integer) = nothing, delay::Union(Nothing,Float64) = nothing)
+    n_cur = ccall(:jl_profile_maxlen_data, Csize_t, ())
+    delay_cur = ccall(:jl_profile_delay_nsec, Uint64, ())/10^9
+    if n == nothing && delay == nothing
+        return int(n_cur), delay_cur
+    end
+    nnew = (n == nothing) ? n_cur : n
+    delaynew = (delay == nothing) ? delay_cur : delay
+    init(nnew, delaynew)
+end
+
 function init(n::Integer, delay::Float64)
     status = ccall(:jl_profile_init, Cint, (Csize_t, Uint64), n, iround(10^9*delay))
     if status == -1
@@ -108,7 +119,7 @@ function fetch()
     len = len_data()
     maxlen = maxlen_data()
     if (len == maxlen)
-        warn("The profile data buffer is full; profiling probably terminated\nbefore your program finished. To profile for longer runs, call Profile.init()\nwith a larger buffer and/or larger delay.")
+        warn("The profile data buffer is full; profiling probably terminated\nbefore your program finished. To profile for longer runs, call Profile.init\nwith a larger buffer and/or larger delay.")
     end
     pointer_to_array(get_data_pointer(), (len,))
 end

doc/stdlib/profile.rst

@@ -272,9 +272,11 @@ backtraces will be filled. If that happens, the backtraces stop but
 your computation continues. As a consequence, you may miss some
 important profiling data (you will get a warning when that happens).
 
-You can configure the relevant parameters this way::
+You can obtain and configure the relevant parameters this way::
 
+  Profile.init()            # returns the current settings
   Profile.init(n, delay)
+  Profile.init(delay = 0.01)
 
 ``n`` is the total number of instruction pointers you can store, with
 a default value of ``10^6``. If your typical backtrace is 20
@@ -325,13 +327,15 @@ Function reference
    Supply the vector ``data`` of backtraces and a dictionary
    ``lidict`` of line information.
 
-.. function:: init(n::Integer, delay::Float64)
+.. function:: init(; n::Integer, delay::Float64)
 
    Configure the ``delay`` between backtraces (measured in seconds),
    and the number ``n`` of instruction pointers that may be
    stored. Each instruction pointer corresponds to a single line of
    code; backtraces generally consist of a long list of instruction
-   pointers. Default settings are ``n=10^6`` and ``delay=0.001``.
+   pointers. Default settings can be obtained by calling this function
+   with no arguments, and each can be set independently using keywords
+   or in the order ``(n, delay)``.
 
 .. function:: fetch() -> data
 

src/profile.c

@@ -429,6 +429,11 @@ DLLEXPORT size_t jl_profile_maxlen_data(void)
     return bt_size_max;
 }
 
+DLLEXPORT u_int64_t jl_profile_delay_nsec(void)
+{
+    return nsecprof;
+}
+
 DLLEXPORT void jl_profile_clear_data(void)
 {
     bt_size_cur = 0;