It is with distinct lack of pride that I release version 0.1 of diskstat 'Geeks in Black Thorn', a tool that allows you to generate the kinds of graphs as presented in my OLS talk 'On faster application startup times: Cache stuffing, seek profiling, adaptive preloading'. The lack of pride is because this release is more a promise of what is to come than how things should be.
The presentation, paper, and software can be found on http://ds9a.nl/diskstat and http://ds9a.nl/diskstat/diskstat-0.1.tar.gz >From the README: The quality of this code is abysmal, for which I squarely blame the fun people at OLS who've been keeping me from my code! (...) The next version will be based on k/jprobes, and will make better use of relayfs features. This also means you won't have to patch your kernel anymore, as long as you compiled with kprobes support. Sample command lines: # mkdir /relay # mount -t relayfs none /relay # ./dumpdiskstat /relay/diskstat0 > dump This will output something like: I think we skipped at 90867, ret=0 I think we hit end at 143016, ret=-1 I think we hit the break again 90867, ret=0 Process the stats. $ ./dswalk < dump It will print out huge latencies encountered: > Large latency 163.352 on line 14146 Total read started: 33888768, total ended: 33888768 Total write started: 1372160, total ended: 1372160 Waiting time: 10.695 seconds Make pretty plots gnuplot plot 'startplaces.dat', 'headplaces.dat' plot 'inflight.dat' Continue reading on http://ds9a.nl/diskstat/README -- http://www.PowerDNS.com Open source, database driven DNS Software http://netherlabs.nl Open and Closed source services - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
