PC’s clock is an oscillator and HPET (high performance event timer) to count oscillator ticks. The time function is therefore \(C(t) = C_0 + p(t) \textrm{HPET}(t)\) where \(p(t)\) is the period of clock ticks and HPET is the tick count. Note, \(p(t)\) is varying slowly and therefore \(C(t)\) is not...
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Parallelism by tee in bash
This is what I did in my simulation processing code.
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Reservoir Sampling with Uniform Probability
Assume you have a million lines of data in ordered pairs and you want to plot it in GNU Plot. That’s likely to kill your computer. Indeed, plotting a million dots on a graph does not give more information than that plotting a thousand dots. Therefore, how we can sample...
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Threading performance checker using GDB
gdb -ex “set pagination 0″ -ex “thread apply all bt” –batch -p ${pid} | awk ‘BEGIN { s = “”; } /Thread/ { print s; s = “”; } /^\#/ { if (s != “” ) { s = s “,” $4} else { s = $4 } } END...
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Kandula et al (2009) Flyways To De-Congest Data Center Networks (HotNets)
This paper says, if we require a network to be not oversubscribed, the cost is high. For example, if we use fat-tree topology, the networking cost is 2-3x of a tree topology. Using VL2 is even 4-5x. However, it is not necessary to prevent oversubscription because in most of the...
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