P4's really suck at system calls. A 2.8GHz P4 does a simple system call
a lot _slower_ than a 500MHz PIII.
The P4 has problems with some other things too, but the "int + iret"
instruction combination is absolutely the worst I've seen. A 1.2GHz
Athlon will be 5-10 times faster than the fastest P4 on system call
overhead.
HOWEVER, the P4 is really good at a lot of other things. On average, a
P4 tends to perform quite well on most loads, and hyperthreading (if you
have a Xeon or one of the newer desktop CPU's) also tends to work quite
well to smooth things out in real life.
In short: the P4 architecture excels at some things, and it sucks at
others. It _mostly_ tends to excel more than suck.
Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/