Git bash startup is slow

[kjeremy]

Starting git bash from the start menu (for example) takes about 5 seconds enter a useable state. Doing the same in the git-1.9.5-preview release is virtually instantaneous.

This is a regression from the git-1.9.5-preview release.

[dscho]

Please follow the steps described in https://github.com/msysgit/msysgit/wiki/Diagnosing-why-Git-is-so-slow to diagnose the problem. It does not take 5 seconds here.

[calle2010]

For me starting git-bash.exe takes around 3 seconds (SSD, more than enough RAM). I tried the "set -x" at the mentioned Wiki page and everything is fast after the mintty window is shown.

Even if I start mintty.exe directly it takes 2-3 seconds before the window is shown.

Then I pulled my network cable. For some minutes mintty.exe started only after more than 10 seconds. Later, while network cable still pulled, it started instantaneously. So I guessed when mintty.exe starts some network lookup is tried.

What I found is that mintty opens an LDAP(?) connection (port 389) to one of my company's servers. This is closed after startup. It keeps open a listening UDP port on 127.0.0.1.

Note: The delay before mintty.exe window comes up happens only when starting it from Windows Explorer or cmd.exe command line. When I start mintty.exe from Git Bash it starts instantaneously.

A similar issue is described here: http://stackoverflow.com/questions/28410852/startup-is-really-slow-for-all-cygwin-applications

From first answer, solution 1, I took the two commands

$ mkpasswd -c > /etc/passwd
$ mkgroup -c > /etc/group

and entered those while running git-bash.exe. Even without the change to nsswitch.conf the issue is solved. I don't see LDAP connections anymore. git-bash.exe starts as fast as any other small Windows program. cmd.exe still starts faster, though.

Tip for the user that comes here to read how to speed up git-bash.exe: The fastest way to create another Git Bash window is to press Alt+F2 from the first Git Bash window.

[kjeremy]

Interesting... I'll try that out. They talk about it in the cygwin release notes: https://cygwin.com/ml/cygwin-announce/2015-02/msg00009.html

[kjeremy]

@calle2010 I tried the fix from your comment + the nsswitch configuration and results are not consistent. Sometimes it starts instantaneously and other times it takes 5-20 seconds.

I bet it's related to ldap somehow because if I'm on the work domain it tends to start up faster. Still this is a change from the latest stable.

[mscrivo]

@kjeremy I've got the exact same issue as you. Startup speed is very inconsistent, anywhere from 1s to 5s. The above tip did nothing for me. set -x and git trace do not help either as the delay occurs before either of those start spitting out info.

I am using Conemu and the startup delay only seems to happen there, but the delay never happened with 1.9.5.

I'm using: "set MSYSTEM=MINGW64 & "%ProgramFiles%\Git\usr\bin\sh.exe" --login -i" as my Conemu task command.

[dscho]

@mscrivo maybe setting HOME in addition to MSYSTEM would help?

[mscrivo]

@dscho Didn't help. Although, I just noticed in process explorer that when the delay happens, it's trying to connect to our ldap server and that connection hangs for a while occasionally. Which seems in line with what @calle2010 is saying above. Curious why that didn't work.

[mscrivo]

I just noticed @calle2010's command has a typo, he references "cpasswd", I changed the filename to "passwd" and that does indeed fix the problem!

[kjeremy]

It only fixed it until I disconnected from the domain and then the problem
came back. It seems intermittent.

On Tue, Jun 16, 2015 at 11:20 AM, mscrivo notifications@github.com wrote:

I just noticed @calle2010 https://github.com/calle2010's command has a
type, he references "cpasswd", I changed the filename to "passwd" and that
does indeed fix the problem!

—
Reply to this email directly or view it on GitHub
#193 (comment)
.

[calle2010]

I changed my comment to fix the typo.

[dscho]

Thank you all for the analysis. Based on it, I think the best way to fix this would be to introduce a new dbfast option for passwd and group in the nsswitch.conf file. The idea is to copy-edit the db handling and then limit it to the local machine and the current account (because we do not really need complete user/group data, in contrast to Cygwin).

[dscho]

This would be the way to tackle this issue:

• Build msys2-runtime from scratch: https://github.com/git-for-windows/git/wiki/Building-msys2-runtime
• Add "dbfast" handling here, here and in winsup/cygwin/passwd.cc
• Start implementing the "dbfast" handling by adding pwdgrp fields here and here, then adding handling in all the add_*_from_windows() and eventually patch fetch_account_from_windows()

Of course, all of this assumes that the problem actually is in that passwd/group handling.

Maybe a sensible first step would be to call Bash from a cmd.exe window via

cd <top-level>
usr\bin\strace -o strace.out usr\bin\bash.exe --login -i

(maybe running it without -o strace.out first to see where exactly it spends a lot of time)

[dscho]

Hrm. Apparently there is nobody willing to work on this except for me. But I have no way to reproduce because I have no machine that is connected to LDAP.

I fear that it will take more enthusiasm from a developer with access to a setup displaying the behavior in question.

Alternatively, if anybody would at least provide clear and simple instructions how to reproduce it on my side, that would be helpful.