Botched GC timings for multi-threaded programs?

[luismbo]

<nikodemus> luis: how do you detect the start/stop of GC?
<luis> nikodemus: with a big fat HACK.
<nikodemus> hah
<luis> I temporarily redefine SB-KERNEL:SUB-GC.
<nikodemus> that doesn't really give you accurate accounting when multiple
threads are running
<nikodemus> what you really want to do is to wrap SB-KERNEL::COLLECT-GARBAGE,
i think. that's called only after all other threads have been
stopped
<luis> nikodemus: that makes sense, but I'd have to check if my timings are
process-wide. I don't remember.