[Win32utils-devel] IO.read questions

Daniel Berger djberg96 at gmail.com
Fri May 4 15:35:39 UTC 2012


On Thu, May 3, 2012 at 8:48 AM, Daniel Berger <djberg96 at gmail.com> wrote:
> On Thu, May 3, 2012 at 5:58 AM, Luis Lavena <luislavena at gmail.com> wrote:
>> On Thu, May 3, 2012 at 2:25 AM, Daniel Berger <djberg96 at gmail.com> wrote:
>>>
>>> Oh, I plan on it. In fact I was playing with the ffi branch of the
>>> win32-nio library again today. The NIO.read benchmarks are pretty
>>> good. Much faster than the default IO.read method.
>>>
>>
>> Please note that NIO.read might not be doing all the legwork IO.read
>> is already doing in relation to encodings.
>>
>> Which, along with others, I think is overkill.
>
> True, I thought that option was a bit silly, since users can always
> encode after the fact if they want.
>
> Performance is being hampered somewhat by having to do newline
> conversions, but the results are good:
>
> c:\Users\djberge\Repositories\win32-nio>rake bench
> ruby -Ilib benchmarks/win32_nio_benchmarks.rb
> Small file created (588k)
> Medium file created (6mb)
> Large file created (58mb)
> Huge file created (618mb)
>
>                           user     system      total        real
> IO.read(small)         0.016000   0.016000   0.032000 (  0.027001)
> IO.read(medium)        0.234000   0.062000   0.296000 (  0.295017)
> IO.read(large)         2.184000   0.484000   2.668000 (  2.687154)
> IO.read(huge)         22.245000   5.007000  27.252000 ( 27.283561)
>
> NIO.read(small)        0.016000   0.000000   0.016000 (  0.017001)
> NIO.read(medium)       0.172000   0.188000   0.360000 (  0.617035)
> NIO.read(large)        1.263000   1.014000   2.277000 (  4.820276)
> NIO.read(huge)        13.822000   7.909000  21.731000 ( 32.729872)
>
> Minor improvements for smaller files, but the savings gets better as
> the files get bigger. It's a shame there's no text mode for
> CreateFile.
>
> BTW, using FILE_FLAG_NO_BUFFERING with a sector aligned buffer didn't
> yield any noticeable improvements that I could see.

Hm, I ran the numbers again today and suddenly NIO is slower. Dunno
what to make of that.

Regards,

Dan


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