Re: last snapshot is not better than previous version

[Denis Excoffier <cygwin@Denis-Excoffier.org>]

> On 2016-06-04 05:52, John Hood wrote:
> 
> Corinna asked me to look at this since I coded the select()-related changes she mentioned.  I can't reproduce either of your cases.
Thank you for your help.
> 
> Some things I'll mention:
> 
> 1) Your Cygwin install seems to be in your Windows home directory. There's nothing wrong with that but it is unusual.  Is there some reason the usual location doesn't work?
This PC belongs to my company, and i don't know where to write if not in my home directory. C:\CYGWIN is not an option for me (permission denied). I have no special/administrator/whatever right, only basic user. Cygwin is installed with the "Just Me" option.
> 
> 2) The cygcheck output shows you being a member of over 50 groups, is this system in a domain?  Are any network shares involved?  (I tried mounting a local network share, then using ls.  It was 10 times slower-- but that was still only 4 seconds to list 11000 files.)
Yes this system is in a domain. No network shares are involved. For these tests, i'm not connected to anything, only local drives.
> 
> 3) You have many thousands of packages installed.  It's not the complete Cygwin set but it is a substantial fraction.  It might be worth trying an install with a smaller number of packages.  Are you running these tests on the same Cygwin install but with different DLLs installed, or on different Cygwin installs?
I usually install all the packages (but not the test ones), except the Debug category for which i keep the default. I usually also install each test Cygwin package as soon as it is announced, including the cygwin-devel package (currently there are none). I also install each new snapshot as soon i can see it.
For each cygwin version installed (regular package, test package, snapshot) and immediately after installation, i compile a fresh cygwin1.dll from the corresponding source package (modifying 'define SYMLOOP_MAX' from 10 to 32 since 10 is definitely too small for me). If everything goes well, i switch to the fresh cygwin1.dll and perform my usual business with it.
For this particular 20160520 snapshot (now 20160531) i've exercised this whole process, then observed the abovementioned slowness, then switched back to the cygwin1.dll from 2.5.1-1, keeping the other files from cygwin-20160520.tar.xz (then installed cygwin-20160531.tar.xz, then switched back again to the cygwin1.dll from 2.5.1-1).
In other terms, "with snapshot" means "with the snapshot fully installed" (all files from cygwin-yyyymmdd.tar.xz). "without snashot" means the same, except that the cygwin1.dll is replaced by the one from 2.5.1-1.
> 
> 4) You've given an interpretation of the strace output that you see, but it might be useful to see the actual strace output for your two test cases.  Perhaps the noisy logging for select() is an effect of the problem, rather than its cause.  Could you run them again (also with the -d flag, which will help us see where the time goes), and send them in email?
I'll send this by private email. Please wait a little.

Regards,

Denis Excoffier.
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