Re: Differences between FreeBSD and Linux system call mechanism

Petko Manolov (petkan@varel.bg)
Thu, 03 Sep 1998 13:27:21 +0000

> Terry Lambert wrote:
>
> Linux uses a call-gate based kernel entry, which is TSS based, and

It is not TSS baset, it is _trap_ based and uses int 0x80. Look
at .../linux/arch/i386/kernel/traps.c and entry.S

> therefore takes more CPU cycles on a contect switch than strictly
> required. The FreeBSD mechanism for kernel entry (and subsequet
> context switch) is threfore more efficient than that used by Linux.

I don't know what is the BSD mechanism, but in Linux tasks are software
switched since 2.1.1xx something. Read the note before __switch_to() in
.../linux/arch/i386/kernel/process.c. I prefer _safe_ instead of _fast_
task switching.

Petkan

--
Petko Manolov, http://www.varel.bg/~petkan


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