On Fri, 2010-03-05 at 15:01 +0800, leon wrote: > Hi there, > > Very appreciated about your "blktrace", "btt" and > gelato_ICE06apr_blktrace_brunelle_hp.pdf. They are quite powerful! > > I am using blktrace-1.0.1-4.3.i586 on kernel 2.6.31.8, but the btt > output seems a little bit different from that pdf. This doc only > explained Q2I I2D D2C Q2C > > Can anybody help to explain the detail meaning of: > > Q2Q > Q2G > G2I > Q2M > M2D > > Or is there any more detailed document about Q, G, I, M, D etc? > > Thank you very much > Leon Hi Leon - Check out the btt.pdf generated by "make docs" - in a nutshell, 'Q' traces indicates entry into the block I/O layer (more or less) so 'Q2Q' would be the time between entries into the block I/O layer. 'G' is the 'request get' trace - so 'Q2G' shows the time needed to get a request. 'I' is the insert trace - so 'G2I' is how long it then took to find the right queue spot to put the request on. 'M' is the merge trace - so 'Q2M' indicates how long it took to find & merge an incoming I/O, whilst 'M2D' indicates how long it took for that request to be 'issueD' - sent down to the underlying device driver. Regards, Alan -- To unsubscribe from this list: send the line "unsubscribe linux-btrace" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
