Messages in this thread | | | From | bob <> | Date | Sun, 22 Sep 2002 17:29:21 -0400 (EDT) | Subject | Re: [ltt-dev] Re: [PATCH] LTT for 2.5.38 1/9: Core infrastructure |
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Linus Torvalds writes: > > >From what I've seen from the LTT thing, it's too heavy-weight to be good
Not true anymore.
> I suspect we'll want to have some form of event tracing eventually, but > I'm personally pretty convinced that it needs to be a per-CPU thing, and > the core mechanism would need to be very lightweight. It's easier to build > up complexity on top of a lightweight interface than it is to make a > lightweight interface out of a heavy one.
We have removed locks (code now atomically reserves space in the trace buffer), significantly reduced the cost of taking timestamps by using the real-time clock, and are in the process of implementing per-CPU buffers. As per previous email, the intent is to get only the core infrastructure into the kernel and keep trace points as patches. Some of the work going into LTT is modeled after the tracing infrastructure in K42, which is extremely lightweight, lock-free, and designed for multiprocessors.
Robert Wisniewski The K42 MP OS Project Advanced Operating Systems Scalable Parallel Systems IBM T.J. Watson Research Center 914-945-3181 http://www.research.ibm.com/K42/ bob@watson.ibm.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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