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There are many possible causes for this.
This answer is more a list of things to look into than a set of solutions.
If your terminal windows suddenly began starting slowly
after a Cygwin upgrade, it may indicate issues in the authentication setup.
For almost all its lifetime, Cygwin has used Unix-like
/etc/passwd and /etc/group
files to mirror the contents of the Windows SAM and AD databases.
Although these files can still be used, since Cygwin 1.7.34, new installations
now use the SAM/AD databases directly.
To switch to the new method, move these two files out of the way and
restart the Cygwin terminal. That runs Cygwin in its new default mode. If
you are on a system that isn't using AD domain logins, this makes Cygwin
use the native Windows SAM database directly, which may be faster than the
old method involving /etc/passwd and such.
At worst, it will only be a bit slower. (Which situation applies depends on
the benchmark you run.)
The 1.7.35 release is expected to bring improvements in the area by
limiting the number of cases in which DC is contacted in default setup, but
it will also limit the potential of the new integration scheme. I.e. Cygwin
will not try to lookup your home directory or default shell from AD/SAM. For
that, you will need to alter /etc/nsswitch.conf
to suit your needs.
However, if you are still experiencing very slow shell startups,
see below for a list of things to try to make startup times more manageable.
For AD client systems: common cause of slow Cygwin
Terminal startups is a bad DNS setup. Many things that occur during a Cygwin
Terminal startup require fast DNS lookups. This is something for AD
administrators to look into.
This may affect both local and remote domain controllers. Another cause for AD client system is slow DC replies,
commonly observed in configurations with remote DC access. Cygwin Terminal
queries information about every group you're in to populate local cache. You
may speed up this process a little by caching your own information in local
files. Run this code in a terminal with write access to /etc:
getent passwd $(id -u) > /etc/passwd
getent group $(id -G) > /etc/group
And set /etc/nsswitch.conf as follows:
passwd: files db
group: files db
This will limit the need for Cygwin to contact DC, while still allowing for
additional information to be retrieved from DC, when f.e. listing remote
directories. As an alternative, or to further speed up the slow DC
resolution/answers, consider running cygserver
as local caching module.
Every new Cygwin process tree will check with cygserver before trying to
address DC directly. Less preferable, but possible solution would be to
create permanent cache of the authentication data in an old-fashioned way.
To do this, re-run mkpasswd
and mkgroup, then put the
following into /etc/nsswitch.conf to make
Cygwin treat these files as read-only local caches of your AD database:
passwd: files
group: files
By leaving out the "db" option, we are telling the Cygwin DLL not to even
try to do AD lookups. If your AD
servers are slow, this local cache will speed things up. The downside is
the old stale cache problem: any time the AD databases change, your local
cache will go out of date until you update the files manually. If none of the above helps, the best troubleshooting method is to run your
startup scripts in debug mode. Right-click your Cygwin Terminal icon, go to
Properties, and edit the command. It should be something like C:\cygwin\bin\mintty.exe -i /Cygwin-Terminal.ico -.
Assuming you are using Bash for your login shell, change it to
C:\cygwin64\bin\mintty /bin/bash -lx.
That will cause it to write out a line for every command it runs. A slow
Cygwin Terminal launch usually means one or more of the many commands Cygwin
runs when starting up will take a long time. That will be your clue as to
what's going on. |