cvs commit: src/sys/amd64/amd64 bpf_jit_machdep.c bpf_jit_machdep.h src/sys/conf files files.amd64 files.i386 options.amd64 options.i386 src/sys/i386/i386 bpf_jit_machdep.c bpf_jit_machdep.h src/sys/net bpf.c bpf_jitter.c bpf_jitter.h bpfdesc.h

[Jung-uk Kim]

On Monday 19 December 2005 01:38 pm, Jeremie Le Hen wrote:
> Hi, Jung-uk,
>
> On Tue, Dec 06, 2005 at 02:58:12AM +0000, Jung-uk Kim wrote:
> > jkim        2005-12-06 02:58:12 UTC
> >
> >   FreeBSD src repository
> >
> >   Modified files:
> >     sys/conf             files files.amd64 files.i386
> >                          options.amd64 options.i386
> >     sys/net              bpf.c bpfdesc.h
> >   Added files:
> >     sys/amd64/amd64      bpf_jit_machdep.c bpf_jit_machdep.h
> >     sys/i386/i386        bpf_jit_machdep.c bpf_jit_machdep.h
> >     sys/net              bpf_jitter.c bpf_jitter.h
> >   Log:
> >   Add experimental BPF Just-In-Time compiler for amd64 and i386.
> >
> >   Use the following kernel configuration option to enable:
> >
> >           options BPF_JITTER
> >
> >   If you want to use bpf_filter() instead (e. g., debugging), do:
> >
> >           sysctl net.bpf.jitter.enable=0
> >
> >   to turn it off.
> >
> >   Currently BIOCSETWF and bpf_mtap2() are unsupported, and
> > bpf_mtap() is partially supported because 1) no need, 2) avoid
> > expensive m_copydata(9).
> >
> >   Obtained from:  WinPcap 3.1 (for i386)
>
> Though the name looks quite exciting, I don't really know what it
> is. I tried to look on WinPcap's website as well as searching on
> Google, but found nothing relevant.  Could you explain in a few
> words what it is and the difference with the old bpf(4) behaviour,
> please ?

BPF JIT compiler converts BPF instructions into native machine code 
when BIOCSETF ioctl is issued, and then the native filter is used to 
filter packets instead of bpf_filter(), which is a simple virtual 
machine.

> Does this change will lead to a new note in bpf(4) manual 
> page once it won't be experimental any more ?

Yes.  Maybe bpf(9), too.

Jung-uk Kim