Linked by Eugenia Loli on Mon 28th Apr 2003 15:48 UTC
Original OSNews Interviews Today we feature an in-depth interview with three members of FreeBSD's Core (Wes Peters, Greg Lehey and M. Warner Losh) and also a major FreeBSD developer (Scott Long). It is a long read, but we touch a number of hot issues, from the Java port to corporate backing, the Linux competition, the 5.x branch and how it stacks up against the other Unices, UFS2, the possible XFree86 fork, SCO and its Unix IP situation, even re-unification of the BSDs. If you are into (any) Unix, this interview is a must read.
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Re: phil
by Bascule on Tue 29th Apr 2003 20:49 UTC

Bascule: However, FreeBSD 5.0's locking granularity is much finer than in Linux.

phil: That really isn't true at all. Both Linux 2.5 and FBSD 5.0 continue to use a global lock although the former currently uses it far less than the latter (is seems this is largely because work to push Giant down hasn't progressed very far yet.)

I probably should say something along the lines of "theoretical locking granularity"

However I'm simply going off the number of locks present in each of the various kernel subsystems, and there are significantly more in FreeBSD.

From what I've read of recent Linux kernel ChangeLogs though (and due to overall stalls in FreeBSD development) Linux is currently farther along in removing the global lock. A considerable number of FreeBSD device drivers still require the Giant lock (see http://www.freebsd.org/projects/busdma/ for a complete list) whereas Linux has been working on removing it for the past three kernel revisions. So, in response to Linux being farther along than FreeBSD in removing the BKL, all I can really say is "One would hope so"

Linux could, in theory, have the BKL removed by the 2.6 release, whereas in the case of FreeBSD the driver rewrites would necessitate the removal as part of 6.0 at the minimum.

As far as kernel subsystems go, the only area where Giant continues to see considerable use is in support for non-native ABIs (see http://www.freebsd.org/smp/ for more information) This issue isn't even comparable between Linux and FreeBSD as Linux doesn't really need robust support for any ABI but its own.