cvs commit: src/sys/amd64/amd64
mp_machdep.csrc/sys/amd64/include cpufunc.h src/sys/i386/i386
mp_machdep.c src/sys/i386/include cpufunc.h
peterjeremy at optushome.com.au
Mon May 16 01:00:41 PDT 2005
On Sun, May 15, 2005 at 01:13:56PM -0700, Nate Lawson wrote:
>My point was that FreeBSD (like most general-purpose OS) has many timing
>channels that are comparably as effective for an attacker as HTT.
If you take the bandwidth of the timing channel into account, I don't
believe there are any other timing channels that come anywhere near the
HTT attack. Maybe Colin has a better idea of what other timing channels
exist and how they compare to HTT.
>Disabling HTT does not significantly reduce an attacker's likelihood of
>success since they can just use another timing channel. However, it
>does disable a useful feature. Are we going to disable SMP next?
How useful is HTT on FreeBSD? FreeBSD does not have a HTT-aware
scheduler at present and I don't believe there are even any plans to
make either scheduler HTT-aware. Without this, you only gain a benefit
if you are running fairly specific workloads.
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