Performance of term_to_binary vs Bbinary_to_term

[Valentin Micic]

Hmmm… I realised that my previous email may be seen as a comment rather than a question, so let me ask the question clearly.

Given that binary_to_term/1 is about two orders of magnitude slower than term_to_binary/1, is there anyone out there that may have a reasonable explanation for that?

Kind regards

V/

> On 06 Jun 2021, at 02:07, Valentin Micic <v@REDACTED> wrote:
> 
> Hi all,
> 
> I did some performance measurement recently that included conversion of an arbitrary erlang term to its external binary representation via term_to_binary/1, as well as reversing the result using binary_to_term/1.
> 
> I’ve noticed that term_to_binary/1 is significantly faster than binary_to_term/1.
> 
> Also, I’ve observed that binary_to_term/1 performance gets considerably worse as complexity of specified term increases, whilst term_to_binary/1 maintains (more-less) steady performance.
> 
> (cig@REDACTED)40> tconvert:run( a, 10000000 ).
> 
> term_to_binary/1 RETURN VALUE:<<131,100,0,1,97>>
> REQUEST COUNT:10000000
> ELAPSED TIME (usec):97070
> TIME PER REQUEST (usec): 0.009707
> PROJECTED RATE (req/sec): 103018440.30081384
> 
> binary_to_term/1 RETURN VALUE:a
> REQUEST COUNT:10000000
> ELAPSED TIME (usec):3383483
> TIME PER REQUEST (usec): 0.3383483
> PROJECTED RATE (req/sec): 2955534.2822765773
> ok
> 
> (cig@REDACTED)41> tconvert:run( {a,<<1,2,3>>, b, [1,2,3], c, {1,2,3}, d, #{a=>1, b=>2, c=>3}}, 10000000 ).
> 
> term_to_binary/1 RETURN VALUE:<<131,104,8,100,0,1,97,109,0,0,0,3,1,2,3,100,0,1,
>                                 98,107,0,3,1,2,3,100,0,1,99,104,3,97,1,97,2,97,
>                                 3,100,0,1,100,116,0,0,0,3,100,0,1,97,97,1,100,
>                                 0,1,98,97,2,100,0,1,99,97,3>>
> REQUEST COUNT:10000000
> ELAPSED TIME (usec):97307
> TIME PER REQUEST (usec): 0.0097307
> PROJECTED RATE (req/sec): 102767529.57135664
> 
> binary_to_term/1 RETURN VALUE:{a,<<1,2,3>>,
>                                  b,
>                                  [1,2,3],
>                                  c,
>                                  {1,2,3},
>                                  d, 
>                                  #{a => 1,b => 2,c => 3}}
> REQUEST COUNT:10000000
> ELAPSED TIME (usec):8747426
> TIME PER REQUEST (usec): 0.8747426
> PROJECTED RATE (req/sec): 1143193.4377038456
> ok
> 
> 
> 
> I’ve performed testing on R21.1.
> Any thoughts?
> 
> V/

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