bug#31138: Native json slower than json.el

[Dmitry Gutov]

On 22.04.2019 15:07, Eli Zaretskii wrote:
> I don't know why.  In my profiles I enlarged the iteration count to
> 100, and also enlarged the sampling frequency.  Maybe that's the
> reason.

I posted my invocations here, with all arguments. I didn't see yours.

> The percentage taken by decode_coding_utf_8 didn't change as
> result, FWIW.

Maybe it's not the only bottleneck. What about produce_chars? And 
malloc, of course. Here's the top of my profiling report again:

 6.00%   229  emacs    emacs                 [.] decode_coding_utf_8
 5.31%   206  emacs    libc-2.27.so          [.] malloc
 4.57%   177  emacs    emacs                 [.] produce_chars
 4.12%   164  emacs    libc-2.27.so          [.] malloc_consolidate
 4.05%   161  emacs    libc-2.27.so          [.] cfree@GLIBC_2.2.5
 3.38%   135  emacs    libc-2.27.so    [.] __memmove_avx_unaligned_erms
 3.23%   125  emacs    emacs                 [.] store_symval_forwarding
 2.63%   102  emacs    emacs                 [.] do_symval_forwarding
 2.58%   104  emacs    libc-2.27.so          [.] _int_malloc
 2.58%   100  emacs    emacs                 [.] set_buffer_internal_2
 2.41%    93  emacs    emacs                 [.] allocate_vectorlike
 2.08%    81  emacs    emacs                 [.] json_to_lisp
 1.90%    81  emacs    emacs                 [.] detect_coding_utf_8
 1.85%    72  emacs    emacs           [.] swap_in_symval_forwarding
 1.72%    72  emacs    emacs                 [.] detect_coding
 1.38%    31  emacs    emacs                 [.] insert_from_gap
 1.29%    50  emacs    libjansson.so.4.11.0  [.] json_delete
 1.19%    46  emacs    emacs                 [.] hash_lookup
 1.01%    39  emacs    emacs                 [.] decode_coding
 1.01%    39  emacs    libjansson.so.4.11.0  [.] json_array_get