Re: Windows support

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jul 25, 2007, 18:43 UTC
Message-ID: <alpine.LFD.0.999.0707251131540.3607@woody.linux-foundation.org>
In-Reply-To: <316a20a40707250958w1fe9f6fdn41d75ca704aeb9cd@mail.gmail.com>

On Wed, 25 Jul 2007, Stephen Cuppett wrote:

Show 5 quoted lines

> 
> I don't know if the performance problems are cygwin or not.  More
> knowledgeable people might be able to answer, it's just what I'm
> observing right now.  It could be more fundamental to the types of
> access being performed en masse on inode-based versus NTFS systems.

I think cygwin may add some overhead, but people should really realize that Linux is quite often an order of magnitude faster (or more) than other systems on some very basic operations.

That's especially true for filesystem operations. We really are just that good.

Really simple things like stat/open/read/write/close are just damn fast on Linux. To the point where you really do notice it when you compare to other systems. If something takes hours on Linux, and it's very filesystem-intensive, I'm not at all surprised that it might take days on Windows.

(OS X is probably better than Windows when it comes to filesystem ops, but their memory management absolutely sucks, and I can pretty much guarantee that their filesystem operation latency doesn't hold a candle to Linux, so while I'd expect git to perform "pretty well" on OS X, it's still going to be slower than on Linux)

Linux really *can* be that much faster. You may not see it as much on some other loads, where most of the load is about normal user code, and system call performance is likely to be just a small fraction, but for git, most of what it does is filesystem interactions (I used to think that SHA1's would be noticeable - they're not, and while zlib overhead *can* be noticeable, it usually isn't a big deal except for some very specific cases).

But I bet that git ends up being faster on Windows than many other SCM's are (on Windows). Going native will help, and avoiding things like shell scripting will help a *lot*, but it's still always going to be slower on Windows than it is on Linux. And that is not about anything else than the fact that Linux simply kicks *ss on filesystem ops.

So for doing things like big imports, you might well want to do them on Linux. But that doesn't mean that git will suck on Windows for normal operations.

(It will just not be so *blazingly* fast, ie things like "git status" will generally not be instantaneous).

			Linus