# Tag: working set

• ## Feeling a little bit thrilled about this

Peter J. Denning has referenced my MSc project on the working set in a (draft) article he has written for the CRC Handbook of Computer Science and Engineering.

• ## Working set heuristics and the Linux kernel: my MSc report

My MSc project was titled “Applying Working Set Heuristics to the Linux Kernel” and my aim was to test some local page replacement policies in Linux, which uses a global page replacement algorithm, based on the “2Q” principle. There is a precedent for this: the so-called “swap token” is a local page replacement policy that […]

• ## The binomial distribution, part 1

I think there are now going to be a few posts here which essentially are about me rediscovering some A level maths probability theory and writing it down as an aid to memory. All of this is related as to whether the length of time pages are part of the working set is governed by […]

• ## Done and dusted

I submitted my MSc project report yesterday, so that is it, at least for now, as a computer science student. The report was on “applying working set heuristics to the Linux kernel“: essentially testing to see if there were ways to overlay some elements of local page replacement to the kernel’s global page replacement policy that […]

• ## What that working set comparison graph should have looked like

The graphs look similar but the differences are important – this one (the correct one), appears to confirm that Peter Denning‘s findings about the working set model versus LRU still hold good, at least in broad terms – though this still suggests LRU has better performance characteristics than might be expected. But it’s late now […]

• ## The graph is wrong

Once I published the graph on the previous blog entry I more or less immediately realised it was wrong – it’s not that the curves are wrong: it’s that they are plotted on different scales. The red line plots lifetime curve using the working set of the process based on pages accessed in a certain […]

• ## Working sets compared

NB: This graph is wrong – read more here This shows the ‘lifetime curve’ of Xterm using a time based for determining the working set (ie having a working set of variable size based on recency of access) and a fixed-sized working set. The y-axis measures the average number of instructions executed between faults.

• ## Better algorithm found

Late last night, in a state of some despair, I pleaded for computing power help with my MSc project. Today, having thought about it long and hard I found a better algorithm and speeded the whole thing up by a factor of 50. Like, I am sure, many people previously in my position, my inspiration […]

• ## Help! Computing power or better algorithm required

I have a serious problem with my MSc project. For the first part of this I am seeking to demonstrate/investigate the underlying assumptions about locality, phases of locality and so on that underlie the working set method of VM management. The graphs on other blogs here are some of the output of the test cases […]

• ## Memory demands of a Linux process

The graph above shows the number of (4k) pages required by xterm when running on a 32 bit Linux system – the x axis measures the lifetime of the process (as determined by instructions executed), the y axis the number of pages.