From: Martin Jambon <martin.jambon@ens-lyon.org>
To: caml-list@inria.fr
Subject: Re: AW: [Caml-list] Behaviour of an OCaml program: any possible GC improvement?
Date: Wed, 24 Oct 2012 10:23:16 -0700 [thread overview]
Message-ID: <50882404.2030106@ens-lyon.org> (raw)
In-Reply-To: <1351094857.12207.12@samsung>
On 10/24/2012 09:07 AM, Gerd Stolpmann wrote:
> I don't think you can do much here by just setting parameters. (Btw.,
> there is no need to compile the mli's with -p.)
>
> I've seen high CPU for garbage collection frequently for mainly
> functional programs. It's their nature - you generate lots of
> short-living intermediate results. You can change that only by changing
> the algorithm, e.g. by caching results that would otherwise be
> recomputed again. Some improvement is also possible with simple tricks,
> e.g. if you have something like
>
> Number 0
>
> where Number is from an algebraic type, and you use this term
> frequently, consider to add a constant for it,
>
> let n0 = Number 0
>
> so this isn't reallocated all the time (even: if n=0 then n0 else Number
> n). If this term is used often, this makes a noticeable difference.
Note that the following works too:
if n = 0 then Number 0 (* structured constant *)
else Number n
# type t = Number of int;;
type t = Number of int
# let f () = Number 0;;
val f : unit -> t = <fun>
# f () == f ();;
- : bool = true
Martin
> Am 24.10.2012 17:09:12 schrieb(en) David MENTRE:
>> Hello,
>>
>> 2012/10/24 David MENTRE <dmentre@linux-france.org>:
>> > But, after recompiling everything from scratch and redoing my tests
>> > (taking care of erasing old gmon.out file), I have the same result
>> > (with <spontaneous> calling caml_call_gc). :-(
>>
>> For the sake of completeness, I installed latest OCaml 4.00.1 (for the
>> recall, Linux x86_64 platform), recompiled everything from scratch and
>> re-did my tests. I obtain roughly the same results and the same
>> <spontaneous> calling caml_call_gc. :-(
>>
>> There should be something obvious that I missed.
>>
>> """
>> Flat profile:
>>
>> Each sample counts as 0.01 seconds.
>> % cumulative self self total
>> time seconds seconds calls s/call s/call name
>> 32.54 155.97 155.97 35791 0.00 0.01 mark_slice
>> 19.87 251.24 95.26 58230 0.00 0.00 sweep_slice
>> 12.35 310.42 59.18 88113 0.00 0.00 camlMap__map_1150
>> 6.66 342.34 31.92 94021 0.00 0.00 caml_oldify_mopup
>> 6.57 373.81 31.47 1986040761 0.00 0.00
>> caml_page_table_lookup
>> 4.66 396.17 22.36 3792214394 0.00 0.00 caml_fl_allocate
>> 4.33 416.94 20.77 3799622226 0.00 0.00 caml_oldify_one
>> 3.39 433.18 16.24 3873315118 0.00 0.00
>> caml_fl_merge_block
>> 2.51 445.20 12.03 3792214239 0.00 0.00 caml_alloc_shr
>> 1.38 451.83 6.63 3882908903 0.00 0.00
>> camlData_typing__apply_1255
>> 1.26 457.88 6.05 3792214239 0.00 0.00 allocate_block
>> 1.20 463.62 5.74 1 5.74 5.74
>> caml_realloc_ref_table
>> 0.49 465.99 2.37 188042 0.00 0.00 clear_table
>> 0.44 468.09 2.10 3881730105 0.00 0.00
>> camlData_typing__fun_1445
>> 0.42 470.08 1.99 caml_fl_reset
>> 0.31 471.57 1.50
>> caml_set_allocation_policy
>> 0.28 472.90 1.33 896098 0.00 0.00 caml_gc_message
>> 0.24 474.06 1.16 74 0.02 0.02 camlMap__iter_1144
>> 0.22 475.12 1.06 155 0.01 0.01 caml_add_to_heap
>> 0.11 475.64 0.53
>> camlData_typing__fun_1430
>> 0.07 475.98 0.34
>> camlData_typing__print_vset_1115
>> 0.06 476.29 0.31 94021 0.00 0.00
>> caml_oldify_local_roots
>> 0.04 476.46 0.17 10355866 0.00 0.00
>> camlFormat__doprn_1525
>> 0.03 476.61 0.15 95566109 0.00 0.00 caml_modify
>> 0.03 476.74 0.13 5946696 0.00 0.00
>> camlFormat__kpr_1514
>> 0.03 476.86 0.12 10179867 0.00 0.00
>> camlFormat__advance_loop_1173
>> 0.02 476.97 0.11 16452591 0.00 0.00
>> camlFormat__format_pp_token_1134
>> 0.02 477.05 0.08 15459066 0.00 0.00 caml_putblock
>> 0.02 477.13 0.08 16452612 0.00 0.00
>> camlFormat__add_queue_1087
>> [...]
>> granularity: each sample hit covers 2 byte(s) for 0.00% of 479.32 seconds
>>
>> index % time self children called name
>> 0.00 0.11 25/94021 caml_alloc_small [75]
>> 0.00 0.56 133/94021 caml_alloc_string [51]
>> 0.02 394.48 93863/94021
>> caml_garbage_collection [3]
>> [1] 82.4 0.02 395.15 94021 caml_minor_collection [1]
>> 0.02 297.93 94021/94021
>> caml_major_collection_slice [4]
>> 0.01 97.19 188042/188042 caml_empty_minor_heap
>> [7]
>> 0.00 0.00 94021/94021 caml_final_do_calls
>> [353]
>> -----------------------------------------------
>> <spontaneous>
>> [2] 82.3 0.04 394.50 caml_call_gc [2]
>> 0.00 394.50 93863/93863
>> caml_garbage_collection [3]
>> -----------------------------------------------
>> 0.00 394.50 93863/93863 caml_call_gc [2]
>> [3] 82.3 0.00 394.50 93863 caml_garbage_collection [3]
>> 0.02 394.48 93863/94021 caml_minor_collection
>> [1]
>> 0.00 0.00 93863/97401
>> caml_process_pending_signals [352]
>> -----------------------------------------------
>> 0.02 297.93 94021/94021 caml_minor_collection
>> [1]
>> [4] 62.2 0.02 297.93 94021
>> caml_major_collection_slice [4]
>> 155.97 29.41 35791/35791 mark_slice [5]
>> 95.26 16.33 58230/58230 sweep_slice [6]
>> 0.84 0.00 564126/896098 caml_gc_message [43]
>> 0.00 0.10 4652/4652 start_cycle [76]
>> 0.00 0.01 4651/4651
>> caml_compact_heap_maybe [135]
>> -----------------------------------------------
>> 155.97 29.41 35791/35791
>> caml_major_collection_slice [4]
>> [5] 38.7 155.97 29.41 35791 mark_slice [5]
>> 29.31 0.00 1849494323/1986040761
>> caml_page_table_lookup [16]
>> 0.11 0.00 71582/896098 caml_gc_message [43]
>> 0.00 0.00 1/1 realloc_gray_vals [269]
>> 0.00 0.00 4652/4652 caml_final_update [377]
>> 0.00 0.00 4652/4653 caml_fl_init_merge [375]
>> -----------------------------------------------
>> 95.26 16.33 58230/58230
>> caml_major_collection_slice [4]
>> [6] 23.3 95.26 16.33 58230 sweep_slice [6]
>> 16.24 0.00 3873315117/3873315118
>> caml_fl_merge_block [18]
>> 0.09 0.00 58230/896098 caml_gc_message [43]
>> 0.00 0.00 1/1 caml_finalize_channel
>> [477]
>> -----------------------------------------------
>> 0.01 97.19 188042/188042 caml_minor_collection
>> [1]
>> [7] 20.3 0.01 97.19 188042 caml_empty_minor_heap [7]
>> 31.92 62.08 94021/94021 caml_oldify_mopup [8]
>> 2.37 0.00 188042/188042 clear_table [29]
>> 0.31 0.07 94021/94021
>> caml_oldify_local_roots [58]
>> 0.28 0.00 188042/896098 caml_gc_message [43]
>> 0.05 0.10 9383144/3799622226 caml_oldify_one [14]
>> 0.00 0.00 188042/188042
>> caml_final_empty_young [344]
>> -----------------------------------------------
>> 31.92 62.08 94021/94021 caml_empty_minor_heap
>> [7]
>> [8] 19.6 31.92 62.08 94021 caml_oldify_mopup [8]
>> 20.71 41.37 3787931806/3799622226 caml_oldify_one
>> [14]
>> -----------------------------------------------
>> [...]
>> """
>>
>> Best regards,
>> david
>>
>> --
>> Caml-list mailing list. Subscription management and archives:
>> https://sympa.inria.fr/sympa/arc/caml-list
>> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
>> Bug reports: http://caml.inria.fr/bin/caml-bugs
>>
>>
>
next prev parent reply other threads:[~2012-10-24 17:23 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-24 10:08 David MENTRE
2012-10-24 10:33 ` John Whitington
2012-10-24 12:30 ` David MENTRE
2012-10-24 12:39 ` John Whitington
2012-10-24 12:45 ` Edgar Friendly
2012-10-24 12:53 ` John Whitington
2012-10-24 13:19 ` David MENTRE
2012-10-24 13:27 ` John Whitington
2012-10-24 13:38 ` Oliver Bandel
2012-10-24 14:30 ` David MENTRE
2012-10-24 15:09 ` David MENTRE
2012-10-24 16:07 ` AW: " Gerd Stolpmann
2012-10-24 17:23 ` Martin Jambon [this message]
[not found] ` <1351094817.12207.11@samsung>
2012-10-25 6:48 ` David MENTRE
2012-10-25 7:37 ` David House
2012-10-24 10:38 ` Török Edwin
2012-10-25 10:06 ` David MENTRE
2012-10-25 10:16 ` Török Edwin
2012-10-25 10:19 ` David MENTRE
2012-11-07 11:52 ` David MENTRE
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