Ch 5: Why both kernel headers?
Kevin P. Fleming
kpfleming at linuxfromscratch.org
Wed Sep 15 14:18:28 PDT 2004
Ian Molton wrote:
> userspace uses *software* interrupts to communicate with the kernel,
> which behave in a very similar manner but arent triggered by hadrware
> IRQ lines.
Well, it did :-)
I believe now with the 2.6 kernel on an x86/x86-64 CPU and recent glibc
(in other words, LFS testing/unstable), userspace is using the vDSO to
talk to the kernel on any CPUs that support SYSENTER/SYSCALL. That would
be all modern P3s, P4s, Athlons, etc.
The claim when this was being developed was that it is much faster than
using software interrupts. I can't say from personal experience, though :-)
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