Peter Tribble <peter.tribble at gmail.com> wrote > One of the things I've been planning to add to JKstat for a long while is > the ability to read saved kstat -p output. (I'm essentially done with that, > and it works quite well.) Which got me wondering, and I then started to > ask myself: > > What if we just scrapped the current sar collector (sadc) and just saved > kstat -p output (or something like it) instead?
[snip] > > On one of my machines, a thor, a regular sar datapoint is about 64k. > The kstat -p output is about a meg, but zip gets that down to 160k, and > 7z does significantly better. On a T5140, the sar data is about 20k and > kstat about 2 meg, so there the difference is much larger. But I feel the > idea has promise - in the best case we're almost there already, without > optimizing the saved format or trimming unnecessary data. > > Note that while I mentioned something like kstat -p, I'm not necessarily > thinking of that as the final format - you would want something more > compact, and wouldn't necessarily want to encode numbers as strings. Text isn't a bad format if you have a lot of zeros: in a previous life I had to design a format for spreadsheets, and found that text was - inexpensive to generate (there's very good code for divide-by-ten, using shift and subtract) - compact for small numbers, of which there seems to be a lot. - compressible up the yazoo! --dave c-b -- David Collier-Brown | Always do right. This will gratify Sun Microsystems, Toronto | some people and astonish the rest davecb at sun.com | -- Mark Twain cell: (647) 833-9377, home (416) 223-8968, bridge (877) 385-4099 code 506 9191#
