[Caml-list] [ANN] cconv-0.2

[Caml-list] [ANN] cconv-0.2

[Simon Cruanes]

[-- Attachment #1: Type: text/plain, Size: 1861 bytes --]

Hi everyone,

I'm happy to announce the release of cconv 0.2 [1]. CConv is a
BSD-licensed combinators library for serializing and unserializing data
structures.  It particularity is that it doesn't target a specific
serialization format, but any format that is expressive enough (using
some type machinery involving a few GADTs and visitor patterns).

The rationale is that, for library writers, the current go-to practice
to provide some serialization support is to use type_conv and "with sexp".
This requires camlp4 and a lot of libraries, and forces the choice of
S-expressions on the user. Instead, by providing CConv encoders and
decoders, the user could choose which serialization format (even simple
printing) to use by herself.

To serialize values of type 'a, one can write a value of type ['a
CConv.Encode.encoder] that can be used with any serialization backend;
to unserialize, it's a value of type ['a CConv.Decode.decoder].
Then, cconv ships with three (optional) backends, to Yojson, Bencode and
Sexplib; an ['a encoder] can be used with any of those three (same for
decoders). See the readme [2] for more details.

There will be a ppx_deriving [3] instance [4] soon for automatically
generating decoders and encoders based on types.

If anyone used cconv-0.1, I apologize for the change of interface. The
ideas took time to evolve...

As usual, bug reports, comments, criticism and accusations of
reinventing the wheel are all welcome.

Cheers,

-- 
Simon

[1] https://github.com/c-cube/cconv/tree/0.2
[2] https://github.com/c-cube/cconv/blob/0.2/README.md#usage
[3] https://github.com/whitequark/ppx_deriving
[4] https://github.com/c-cube/ppx_deriving_cconv (work in progress, comments appreciated!)

http://weusepgp.info/
key 49AA62B6, fingerprint 949F EB87 8F06 59C6 D7D3  7D8D 4AC0 1D08 49AA 62B6

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [Caml-list] [ANN] cconv-0.2

[Thomas Gazagnaire]

Hi Simon,

Do you have any benchmarks to compare CConv and similar camlp4 generators?

Thanks,
Thomas

> On 1 Dec 2014, at 09:44, Simon Cruanes <simon.cruanes.2007@m4x.org> wrote:
> 
> Hi everyone,
> 
> I'm happy to announce the release of cconv 0.2 [1]. CConv is a
> BSD-licensed combinators library for serializing and unserializing data
> structures.  It particularity is that it doesn't target a specific
> serialization format, but any format that is expressive enough (using
> some type machinery involving a few GADTs and visitor patterns).
> 
> The rationale is that, for library writers, the current go-to practice
> to provide some serialization support is to use type_conv and "with sexp".
> This requires camlp4 and a lot of libraries, and forces the choice of
> S-expressions on the user. Instead, by providing CConv encoders and
> decoders, the user could choose which serialization format (even simple
> printing) to use by herself.
> 
> To serialize values of type 'a, one can write a value of type ['a
> CConv.Encode.encoder] that can be used with any serialization backend;
> to unserialize, it's a value of type ['a CConv.Decode.decoder].
> Then, cconv ships with three (optional) backends, to Yojson, Bencode and
> Sexplib; an ['a encoder] can be used with any of those three (same for
> decoders). See the readme [2] for more details.
> 
> There will be a ppx_deriving [3] instance [4] soon for automatically
> generating decoders and encoders based on types.
> 
> If anyone used cconv-0.1, I apologize for the change of interface. The
> ideas took time to evolve...
> 
> As usual, bug reports, comments, criticism and accusations of
> reinventing the wheel are all welcome.
> 
> Cheers,
> 
> -- 
> Simon
> 
> [1] https://github.com/c-cube/cconv/tree/0.2
> [2] https://github.com/c-cube/cconv/blob/0.2/README.md#usage
> [3] https://github.com/whitequark/ppx_deriving
> [4] https://github.com/c-cube/ppx_deriving_cconv (work in progress, comments appreciated!)
> 
> http://weusepgp.info/
> key 49AA62B6, fingerprint 949F EB87 8F06 59C6 D7D3  7D8D 4AC0 1D08 49AA 62B6

Re: [Caml-list] [ANN] cconv-0.2

[Simon Cruanes]

[-- Attachment #1: Type: text/plain, Size: 2399 bytes --]

Le Mon, 01 Dec 2014, Thomas Gazagnaire a écrit :
> Do you have any benchmarks to compare CConv and similar camlp4 generators?

Hi Thomas,

I hadn't, but I just wrote very basic ones to compare with
ppx_deriving_yojson (should be similar to camlp4). The code is at
https://github.com/c-cube/cconv/blob/e80ab0e6c458a01b419ea69c7f41d0a350aebbad/bench/run_bench.ml

It only compares times for encoding into Json right now, with the
following results (recursive records first, recursive terms then;
"manual" is a handwritten encoding function, "cconv" the combinators
version, and "deriving_yojson" uses @whitequark's nice deriver):

% ./run_bench.native

benchmark points
Throughputs for "manual", "cconv", "deriving_yojson" each running for at least 4 CPU seconds:
         manual:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 3057270.82/s (n=12846652)
          cconv:  4.21 WALL ( 4.21 usr +  0.00 sys =  4.21 CPU) @ 784724.92/s (n=3300553)
deriving_yojson:  4.21 WALL ( 4.21 usr +  0.00 sys =  4.21 CPU) @ 3065779.07/s (n=12891601)
                     Rate           cconv          manual deriving_yojson
          cconv  784725/s              --            -74%            -74%
         manual 3057271/s            290%              --             -0%
deriving_yojson 3065779/s            291%              0%              --

benchmark terms
Throughputs for "manual", "cconv", "deriving_yojson" each running for at least 4 CPU seconds:
         manual:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 1679609.71/s (n=7057720)
          cconv:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 726619.43/s (n=3051075)
deriving_yojson:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 1624740.65/s (n=6822286)
                     Rate           cconv deriving_yojson          manual
          cconv  726619/s              --            -55%            -57%
deriving_yojson 1624741/s            124%              --             -3%
         manual 1679610/s            131%              3%              --


So yeah, unsurprisingly, there is some overhead :(. There is some
dispatching through records-of-functions going on, because combinators
should work with any backend, whereas specialized encoders can build the
result directly.

-- 
Simon

http://weusepgp.info/
key 49AA62B6, fingerprint 949F EB87 8F06 59C6 D7D3  7D8D 4AC0 1D08 49AA 62B6

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [Caml-list] [ANN] cconv-0.2

[Simon Cruanes]

[-- Attachment #1: Type: text/plain, Size: 5409 bytes --]

So, it is possible (by changing slightly the interface of encoders to
avoid an intermediate structure), to obtain the following (I also added
a benchmark for decoding, comparing cconv to ppx_deriving_yojson):

====== BEGIN BENCH ======

% ./run_bench.native
encoding...

benchmark points
Throughputs for "manual", "cconv", "deriving_yojson" each running for at least 4 CPU seconds:
         manual:  4.18 WALL ( 4.18 usr +  0.00 sys =  4.18 CPU) @ 2826676.15/s (n=11818333)
          cconv:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 941618.68/s (n=3951032)
deriving_yojson:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 2824134.70/s (n=11867014)
                     Rate           cconv deriving_yojson          manual
          cconv  941619/s              --            -67%            -67%
deriving_yojson 2824135/s            200%              --             -0%
         manual 2826676/s            200%              0%              --

benchmark terms
Throughputs for "manual", "cconv", "deriving_yojson" each running for at least 4 CPU seconds:
         manual:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 1125111.48/s (n=4723218)
          cconv:  4.21 WALL ( 4.21 usr +  0.00 sys =  4.21 CPU) @ 789967.68/s (n=3324184)
deriving_yojson:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 1100920.75/s (n=4626069)
                     Rate           cconv deriving_yojson          manual
          cconv  789968/s              --            -28%            -30%
deriving_yojson 1100921/s             39%              --             -2%
         manual 1125111/s             42%              2%              --


decoding...

benchmark points
Throughputs for "cconv", "deriving_yojson" each running for at least 3 CPU seconds:
          cconv:  3.16 WALL ( 3.16 usr +  0.00 sys =  3.16 CPU) @ 493501.11/s (n=1558970)
deriving_yojson:  3.15 WALL ( 3.15 usr +  0.00 sys =  3.15 CPU) @ 1248812.96/s (n=3932512)
                     Rate           cconv deriving_yojson
          cconv  493501/s              --            -60%
deriving_yojson 1248813/s            153%              --

benchmark terms
Throughputs for "cconv", "deriving_yojson" each running for at least 3 CPU seconds:
          cconv:  3.12 WALL ( 3.12 usr +  0.00 sys =  3.12 CPU) @ 577372.88/s (n=1800826)
deriving_yojson:  3.14 WALL ( 3.14 usr +  0.00 sys =  3.14 CPU) @ 1492303.95/s (n=4688819)
                     Rate           cconv deriving_yojson
          cconv  577373/s              --            -61%
deriving_yojson 1492304/s            158%              --
./run_bench.native  45.01s user 1.16s system 99% cpu 46.181 total

====== END BENCH ======

It is still slower to encode records (intermediate list), and decoding also
has some overhead. However, this is the cost of translating
between the type and the JSON representation; I think it should be
negligible compared to the actual IO + printing/parsing cost.

The new, more efficient interface will probably appear in a future release.
With ppx_deriving_cconv that shouldn't be too big a problem...

Cheers,

Le Mon, 01 Dec 2014, Simon Cruanes a écrit :
> Le Mon, 01 Dec 2014, Thomas Gazagnaire a écrit :
> > Do you have any benchmarks to compare CConv and similar camlp4 generators?
> 
> Hi Thomas,
> 
> I hadn't, but I just wrote very basic ones to compare with
> ppx_deriving_yojson (should be similar to camlp4). The code is at
> https://github.com/c-cube/cconv/blob/e80ab0e6c458a01b419ea69c7f41d0a350aebbad/bench/run_bench.ml
> 
> It only compares times for encoding into Json right now, with the
> following results (recursive records first, recursive terms then;
> "manual" is a handwritten encoding function, "cconv" the combinators
> version, and "deriving_yojson" uses @whitequark's nice deriver):
> 
> % ./run_bench.native
> 
> benchmark points
> Throughputs for "manual", "cconv", "deriving_yojson" each running for at least 4 CPU seconds:
>          manual:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 3057270.82/s (n=12846652)
>           cconv:  4.21 WALL ( 4.21 usr +  0.00 sys =  4.21 CPU) @ 784724.92/s (n=3300553)
> deriving_yojson:  4.21 WALL ( 4.21 usr +  0.00 sys =  4.21 CPU) @ 3065779.07/s (n=12891601)
>                      Rate           cconv          manual deriving_yojson
>           cconv  784725/s              --            -74%            -74%
>          manual 3057271/s            290%              --             -0%
> deriving_yojson 3065779/s            291%              0%              --
> 
> benchmark terms
> Throughputs for "manual", "cconv", "deriving_yojson" each running for at least 4 CPU seconds:
>          manual:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 1679609.71/s (n=7057720)
>           cconv:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 726619.43/s (n=3051075)
> deriving_yojson:  4.20 WALL ( 4.20 usr +  0.00 sys =  4.20 CPU) @ 1624740.65/s (n=6822286)
>                      Rate           cconv deriving_yojson          manual
>           cconv  726619/s              --            -55%            -57%
> deriving_yojson 1624741/s            124%              --             -3%
>          manual 1679610/s            131%              3%              --


-- 
Simon

http://weusepgp.info/
key 49AA62B6, fingerprint 949F EB87 8F06 59C6 D7D3  7D8D 4AC0 1D08 49AA 62B6

[-- Attachment #2: Type: application/pgp-signature, Size: 819 bytes --]