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Sat Mar 24 23:28:16 2012 GMT: Romeo and Juliet @ Royal Opera House

Wed Mar 21 22:08:09 2012 GMT: kevent on FreeBSD (Update)

Sun Mar 18 20:55:50 2012 GMT: Multi-threaded epoll/kqueue

I have been playing with edge-triggered epoll in a multi-threaded context on Linux for some time now, but have now also looked at kqueue on FreeBSD/NetBSD. I have to say that I am only using NetBSD (6.- BETA) and FreeBSD (9.0) in a KVM virtual machine, so that might affect things as well.

Anyway, I have written some simple test programs eptest.cc and kqtest.cc (for Linux and NetBSD/FreeBSD respectively). Essentially, they just create a datagram unix-domain socketpair and send 4-byte packets between them. Note that there is only ever a single packet in transit, so there shouldn't be any contention in user space (and there certainly is no explicit locking in the user space code). But I am creating n worker threads to handle event-triggered notifications when data is available to read on these sockets. So there is certainly some kernel space lock contention.

The interesting thing now is how the run-time changes depending on the number of worker threads on each platform. BTW, I am running this on my dual-core AMD64 laptop.

Interestingly, all platforms perform best with a single worker thread and NetBSD/FreeBSD beat Linux with a single worker thread. But the picture changes dramatically when the number of worker threads is increased. While I am only seeing a slight increase in the run time on Linux, NetBSD varies a lot more and the run time on FreeBSD seems to increase exponetially with the number of worker threads.

But as I said, I am not sure how KVM influences these results - so I am sure there is some more investigation to be done...

Mon Mar 05 23:17:44 2012 GMT: The Dream / Song of the Earth @ Royal Opera House

I have just been to a performance of The Dream / Song of the Earth at the Royal Opera House.

Fri Mar 02 23:00:37 2012 GMT: DNSSEC fully enabled for cmeerw.net

I have just been able to set a Delegation Signer (DS) record for cmeerw.net at the registry (cmeerw.org was already enabled a few months ago). This means that the chain of trust is now complete, see cmeerw.net @ DNSViz and cmeerw.net @ DNSSEC Analyzer.

Fri Mar 02 00:03:53 2012 GMT: Rusalka @ Royal Opera House

Just been to a performance of Rusalka at the Royal Opera House - and yes, the staging is ugly (also see here).

Mon Feb 27 21:14:28 2012 GMT: Future Outlook for Eurozone Economy @ London School of Economics

I have just been to a public lecture given by Ewald Nowotny at the London School of Economics about the Future Outlook for Eurozone Economy, although it was more of an overview of the current crisis than an outlook.

Sat Feb 25 17:17:05 2012 GMT: Photos from Kona, HI

Thu Feb 23 23:17:18 2012 GMT: Don Giovanni @ Royal Opera House

Mon Feb 13 00:16:30 2012 GMT: C++ Standards Committee Meeting in Kona, Hawaii

Sun Jan 29 11:03:24 2012 GMT: Prokofiev @ Royal Festival Hall

Mon Jan 23 21:27:05 2012 GMT: The State of the World Economy in 2012 @ London School of Economics


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