>> I've noticed that when working with a very large repository using msysWhat exactly do you mean by "excruciatingly slow"?
>> git, the initial checkout of a cloned repository is excruciatingly
>> slow (80%+ of total clone time). The root cause, I think, is that git
>> does all the file access serially, and that's really slow on Windows.
>>
I just ran a few tests with a big repo (WebKit, ~2GB, ~200k files). A full checkout with git 1.8.4 on my SSD took 52s on Linux and 81s on Windows. Xcopy /s took ~4 minutes (so xcopy is much slower than git). On a 'real' HD (WD Caviar Green) the Windows checkout took ~9 minutes.
If your numbers are much slower, check for overeager virus scanners and probably the infamous "User Account Control" (On Vista/7 (8?), the luafv.sys driver slows down things on the system drive even with UAC turned off in control panel. The driver can be disabled with "sc config luafv start= disabled" + reboot. Reenable with "sc config luafv start= auto").
>> Has anyone considered threading file access to speed this up? InIts probably worth a try, however, in my experience, doing disk IO in parallel tends to slow things down due to more disk seeks.
>> particular, I've got my eye on this loop in unpack-trees.c:
>>
I'd rather try to minimize seeks, ...