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On Tue, 2002-12-17 at 00:09, Linus Torvalds wrote: > On Mon, 16 Dec 2002, Linus Torvalds wrote: > > > > On my P4 machine, a "getppid()" is 641 cycles with sysenter/sysexit, and > > something like 1761 cycles with the old "int 0x80/iret" approach. That's a > > noticeable improvement, but I have to say that I'm a bit disappointed in > > the P4 still, it shouldn't be even that much. > > On a slightly more real system call (gettimeofday - which actually matters > in real life) the difference is still visible, but less so - because the > system call itself takes more of the time, and the kernel entry overhead > is thus not as clear. > > For gettimeofday(), the results on my P4 are: > > sysenter: 1280.425844 cycles > int/iret: 2415.698224 cycles > 1135.272380 cycles diff > factor 1.886637 > > ie sysenter makes that system call almost twice as fast. I'm curious, if this is one of the Dual P4's non-Xeon(say, 2.4 Ghz+?) or if this is one of the Xeons? There seems to be some perceived disparity between which performs how. I think the biggest difference on the Xeon's is the stepping and the cache,(pipeline too?), but not too much else. [...] > 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/ | |||||||||
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