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Message-ID: <2dca96f8-77ab-4e14-a9a1-4a6f543ca16e@gmail.com>
Date: Mon, 18 Dec 2023 07:49:42 +0100
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Subject: Re: Catastrophic Cygwin find . -ls, grep performance on samba share
 compared to WSL&Linux
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To: cygwin@cygwin.com
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From: Marco Atzeri via Cygwin <cygwin@cygwin.com>
Reply-To: Marco Atzeri <marco.atzeri@gmail.com>
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On 18/12/2023 07:22, Dan Shelton via Cygwin wrote:
> On Wed, 6 Dec 2023 at 05:08, Dan Shelton <dan.f.shelton@gmail.com> wrote:
>>
>> Hello!
>> I am unhappy to report a severe performance issue with find -ls, ls -R
>> and grep -r, with Cygwin 3.4.9 and Cygwin 3.5.0 when samba shares are
>> involved.
>>
>> Imagine a directory with 256 subdirs, and each has 256 files per
>> subdir, all on a samba share, samba server is on Linux with tmpfs.
>>
>> mkdir dir1
>> for ((i=0;i<256;i++)) ; do
>>      mkdir "dir1/subdir$i"
>>      for ((j=0; j < 256;j++));do
>>          echo  "j=$j" >"dir1/subdir$i/j$j.txt"
>>      done
>> done
>>
>> Time comparisations then show a dramatic difference, Debian Linux
>> accessing the samba share, WSL accessing the samba share, and Cygwin
>> accessing the samba share:
..
>> Why does that happen?
> 
> It would be nice if someone from the Cygwin authors could assist me in
> figuring out why this happens.
> 
> My working theory is that the extra file and dir lookup calls are for
> soft- and hardlink emulation for file systems which do not have soft-
> or hardlinks?
> If this is correct, then a fix might be to 1) determinate the
> filesystem type (cached, per process lifetime in absence of
> /etc/mnttab) and its boundaries (mount point, and whether other muont
> points are below it) 2) Only use the emulation for FAT filesystems,
> and for NTFS, REFS, SMBFS the native filesystem link is used.
> 
> Help!
> 
> Dan

Is your cygserver running ?


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