From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 14 Oct 2009 11:21:51 -1000 From: Tim Newsham To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Subject: Re: [9fans] Barrelfish Topicbox-Message-UUID: 862e2a02-ead5-11e9-9d60-3106f5b1d025 > Somehow this feels related to the work that came out of Berkeley a year > or so ago. I'm still not convinced what is the benefits of multiple > kernels. If you are managing a couple of 100s of cores a single kernel > would do just fine, once the industry is ready for a couple dozen of > thousands PUs -- the kernel is most likely to be dispensed with anyway. I'm not familiar with the berkeley work. > Did you find any ideas there particularly engaging? I'm still digesting it. My first thoughts were that if my pc is a distributed heterogeneous computer, what lessons it can borrow from earlier work on distributed heterogeneous computing (ie. plan9). I found the discussion on cache coherency, message passing and optimization to be enlightening. The fact that you may want to organize your core OS quite a bit differently depending on which model cpus in the same family you use is kind of scary. The mention that "... the overhead of cache coherence restricts the ability to scale up to even 80 cores" is also eye openeing. If we're at aprox 8 cores today, thats only 5 yrs away (if we double cores every 1.5 yrs). > Roman. Tim Newsham http://www.thenewsh.com/~newsham/