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Date: Mon, 21 Jul 2025 10:07:56 -0600
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Subject: Re: SLOW ls(1) - cygwin dir lookups with WinNT async requests?
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From: Brian Inglis via Cygwin <cygwin AT cygwin DOT com>
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Cc: Brian Inglis <Brian DOT Inglis AT SystematicSW DOT ab DOT ca>
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On 2025-07-21 09:19, Aurélien Couderc via Cygwin wrote:
> On Fri, Jul 18, 2025 at 12:50 PM Andrey Repin <anrdaemon AT yandex DOT ru> wrote:
>>
>> Greetings, Aurélien Couderc!
>>
>>>>>> Stat and ACL info require additional calls.
>>>>
>>>>> Right, but my proposal is to do parallel/async lookups. The Windows NT
>>>>> kernel depends heavily on multithreading and parallelism, of which
>>>>> Cygwin uses nothing right now for dir lookups.
>>>>
>>>> Not an option unless it can be cheaply done under winsup/cygwin/fhandler.
>>>> Most utilities are GNU/BSD/Linux ports, so custom mods would have to be
>>>> submitted and accepted upstream, as we often already have enough patches to
>>>> maintain, to get them to build and work cleanly under Cygwin.
>>
>>> I think you misunderstand me. I am suggesting to improve the Cygwin
>>> implementation of opendir(), readdir() and friends to do Win32/WInNT
>>> calls async to speed up dir listings.
>>
>> If you know how it can be done, why not provide a patch?
> 
> Because I am not YET qualified? This is god level Cygwin hacking
> level, like Corinna Vinschen can do. I'm just a student, doing some
> ReactOS/Windows hacking.

Anyone making such fundamental changes would have to measure performance on SSDs 
and Rust, with/out memory limitations, make changes, and remeasure, possibly 
with a rebuild of coreutils if any changes were made to Cygwin that could affect 
coreutils autoconf.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retrancher  but when there is no more to cut
                                 -- Antoine de Saint-Exupéry

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