[llvm-dev] LLD: time to enable --threads by default

[Rui Ueyama via llvm-dev]

I should've said that do you know if there's an optimized SHA1
implementation that we can use?

On Wed, Nov 16, 2016 at 4:11 PM, Mehdi Amini <mehdi.amini at apple.com> wrote:

> The current implementation was “copy/pasted” from somewhere (it was
> explicitly public domain).
>
> On Nov 16, 2016, at 4:05 PM, Rui Ueyama <ruiu at google.com> wrote:
>
> Can we just copy-and-paste optimized code from somewhere?
>
> On Wed, Nov 16, 2016 at 4:03 PM, Mehdi Amini <mehdi.amini at apple.com>
> wrote:
>
>> SHA1 in LLVM is *very* naive, any improvement is welcome there!
>> It think Amaury pointed it originally and he had an alternative
>> implementation IIRC.
>>
>> —
>> Mehdi
>>
>> On Nov 16, 2016, at 3:58 PM, Rui Ueyama via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>> By the way, while running benchmark, I found that our SHA1 function seems
>> much slower than the one in gold. gold slowed down by only 1.3 seconds to
>> compute a SHA1 of output, but we spent 6.0 seconds to do the same thing (I
>> believe). Something doesn't seem right.
>>
>> Here is a table to link the same binary with -no-threads and
>> -build-id={none,md5,sha1}. The numbers are in seconds.
>>
>>        LLD   gold
>> none   7.82  13.78
>> MD5    9.68  14.56
>> SHA1  13.85  15.05
>>
>>
>> On Wed, Nov 16, 2016 at 1:46 PM, Rafael Espíndola <
>> rafael.espindola at gmail.com> wrote:
>>
>>> On 16 November 2016 at 15:52, Rafael Espíndola
>>> <rafael.espindola at gmail.com> wrote:
>>> > I will do a quick benchmark run.
>>>
>>>
>>> On a mac pro (running linux) the results I got with all cores available:
>>>
>>> firefox
>>>   master 7.146418217
>>>   patch  5.304271767 1.34729488437x faster
>>> firefox-gc
>>>   master 7.316743822
>>>   patch  5.46436812 1.33899174824x faster
>>> chromium
>>>   master 4.265597914
>>>   patch  3.972218527 1.07385781648x faster
>>> chromium fast
>>>   master 1.823614026
>>>   patch  1.686059427 1.08158348205x faster
>>> the gold plugin
>>>   master 0.340167513
>>>   patch  0.318601465 1.06768973269x faster
>>> clang
>>>   master 0.579914119
>>>   patch  0.520784947 1.11353855817x faster
>>> llvm-as
>>>   master 0.03323043
>>>   patch  0.041571719 1.251013574x slower
>>> the gold plugin fsds
>>>   master 0.36675887
>>>   patch  0.350970944 1.04498356992x faster
>>> clang fsds
>>>   master 0.656180056
>>>   patch  0.591607603 1.10914743602x faster
>>> llvm-as fsds
>>>   master 0.030324313
>>>   patch  0.040045353 1.32056917497x slower
>>> scylla
>>>   master 3.23378908
>>>   patch  2.019191831 1.60152642773x faster
>>>
>>> With only 2 cores:
>>>
>>> firefox
>>>   master 7.174839911
>>>   patch  6.319808477 1.13529388384x faster
>>> firefox-gc
>>>   master 7.345525844
>>>   patch  6.493005841 1.13129820362x faster
>>> chromium
>>>   master 4.180752414
>>>   patch  4.129515199 1.01240756179x faster
>>> chromium fast
>>>   master 1.847296843
>>>   patch  1.78837299 1.0329483018x faster
>>> the gold plugin
>>>   master 0.341725451
>>>   patch  0.339943222 1.0052427255x faster
>>> clang
>>>   master 0.581901114
>>>   patch  0.566932481 1.02640284955x faster
>>> llvm-as
>>>   master 0.03381059
>>>   patch  0.036671392 1.08461260215x slower
>>> the gold plugin fsds
>>>   master 0.369184003
>>>   patch  0.368774353 1.00111084189x faster
>>> clang fsds
>>>   master 0.660120583
>>>   patch  0.641040511 1.02976422187x faster
>>> llvm-as fsds
>>>   master 0.031074029
>>>   patch  0.035421531 1.13990789543x slower
>>> scylla
>>>   master 3.243011681
>>>   patch  2.630991522 1.23261958615x faster
>>>
>>>
>>> With only 1 core:
>>>
>>> firefox
>>>   master 7.174323116
>>>   patch  7.301968002 1.01779190649x slower
>>> firefox-gc
>>>   master 7.339104117
>>>   patch  7.466171668 1.01731376868x slower
>>> chromium
>>>   master 4.176958448
>>>   patch  4.188387233 1.00273615003x slower
>>> chromium fast
>>>   master 1.848922713
>>>   patch  1.858714219 1.00529578978x slower
>>> the gold plugin
>>>   master 0.342383846
>>>   patch  0.347106743 1.01379415838x slower
>>> clang
>>>   master 0.582476955
>>>   patch  0.600524655 1.03098440178x slower
>>> llvm-as
>>>   master 0.033248459
>>>   patch  0.035622988 1.07141771593x slower
>>> the gold plugin fsds
>>>   master 0.369510236
>>>   patch  0.376390506 1.01861997133x slower
>>> clang fsds
>>>   master 0.661267753
>>>   patch  0.683417482 1.03349585535x slower
>>> llvm-as fsds
>>>   master 0.030574688
>>>   patch  0.033052779 1.08105041006x slower
>>> scylla
>>>   master 3.236604638
>>>   patch  3.325831407 1.02756801617x slower
>>>
>>> Given that we have an improvement even with just two cores available,
>>> LGTM.
>>>
>>> Cheers,
>>> Rafael
>>>
>>
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>>
>
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