Re: [gentoo-user] Re: Expect a ~15% average slowdown if you use an Intel processor

[Peter Humphrey]

On Friday, 5 January 2018 18:04:10 GMT Ian Zimmerman wrote:
> On 2018-01-05 11:10, Peter Humphrey wrote:
> > Symbol: HAVE_EBPF_JIT [=y]
> > │
> > │ Type  : boolean
> > │   Defined at net/Kconfig:436
> > │   Selected by: X86 [=y] && X86_64 [=y]
> >
> > So it's on, like it or not. This is kernel 4.9.72 on an i7-5820K.
>
> As Rich writes, the HAVE_* symbols are not settable via the UI, and in
> fact do not toggle the inclusion of any code; they are automatically set
> by kconfig to record the _availability_ of some features on the system,
> based on given constraints such as architecture and memory model.

I didn't read that in what Rich wrote, but it's useful anyway - thanks.

> So, HAVE_EBPF_JIT=y just means that BPF JIT _can_ be done on x86.  There
> is a separate BPF_JIT setting to actually enable it.

Well, that doesn't seem to be present here. Just the HAVE_ symbol.

-- 
Regards,
Peter.