Re: rfe: CYGWIN fslinktypes option? Re: Catastrophic Cygwin find . -ls, grep performance on samba share compared to WSL&Linux

[Cedric Blancher <cedric.blancher@gmail.com>]

On Thu, 21 Dec 2023 at 13:17, Martin Wege via Cygwin <cygwin@cygwin.com> wrote:
>
> On Wed, Dec 20, 2023 at 6:21 PM Kaz Kylheku via Cygwin
> <cygwin@cygwin.com> wrote:
> >
> > On 2023-12-17 22:22, Dan Shelton via Cygwin wrote:
> > > It would be nice if someone from the Cygwin authors could assist me in
> > > figuring out why this happens.
> >
> > Cygwin is famously slow; this is nothing new. We are grateful
> > for Cygwin because it makes stuff work at all; if it were blazing
> > fast that would be a bonus.
> >
> > E.g. git operations (clone, rebase, ...); ./configure scripts; ...: all
> > run like molasses.
> >
> > The following is just my fast and loose opinion, shot from the hip,
> > and possibly off or wrong, but it likely has to do with the layering.
> > Cygwin's core API is based on a C library called Newlib. Cygwin bolts
> > Newlib to Windows by means of an additional shim below Newlib that
> > is based on C++ objects, where there is path munging going on and such,
> > and that's where the Win32 calls get made. It's an additional abstraction.
>
> I disagree with that. Ok, part of that is that the layering causes
> more memory allocations and copies, but this is not the root cause.
>
> The root cause is IMO the extra Win32 syscalls (>= 3 per file lookup,
> compared to 1 on Linux) to lookup the *.lnk and *.exe.lnk files on
> filesystems which have native link support (NTFS, ReFS, SMBFS, NFS).
> On SMBFS and NFS it hurts the most, because access latency is the
> highest for networked filesystems.
>
> So my proposal would be to add an option ('fslinktypes') to the CYGWIN
> environment variable to define which types of links are supported:
> default 'all'. which is an shortcut for 'native,lnk,lnkexe'.
> So in case people do not want 'lnk' link support they just add
> CYGWIN+=' fslinktypes:native' to env, to turn off support for
> lnk/lnk.exe style links, and be happy.
>
> @Corinna Vinschen Would that be acceptable?

+1 for this proposal, which is almost the same idea as I proposed in
https://www.mail-archive.com/cygwin@cygwin.com/msg174612.html

Ced
-- 
Cedric Blancher <cedric.blancher@gmail.com>
[https://plus.google.com/u/0/+CedricBlancher/]
Institute Pasteur