Re: [PATCH 3/2] Avoid unnecessary strlen() calls

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mar 20, 2007, 04:45 UTC
Message-ID: <Pine.LNX.4.64.0703192132540.6730@woody.linux-foundation.org>
In-Reply-To: <20070320041843.GA29288@spearce.org>

On Tue, 20 Mar 2007, Shawn O. Pearce wrote:

Show 7 quoted lines

> 
> I tested both patches on a PowerPC G4.  (Apple PowerBook, 1.5 GHz)
> Running on Mac OS X 10.4.8.
> 
> Might be more of a Linux<->Darwin thing; perhaps my isspace is
> significantly slower than yours is...  after all my mmap runs
> like a PC from the 1980s...  ;-)

No, we do a git-specific isspace().

But yeah, a G4 will explain the thing even more than a P4 would. The G4 really isn't a very good uarch compared to the modern x86 ones. Not aggressively out-of-order with deep instruction queues and I don't think it does basically any memop re-ordering at all. I know Apple used to claim that they were the fastest PC around (both with the G4 and the G5), but let's face it, they lied.

The closer to in-order you are, the more instruction scheduling in sw tends to matter.

		Linus