1The code in this directory is used to process data from the mmc tracepoints 2in the kernel. To turn on mmc tracing, do this: 3 4 adb shell echo 1 >/d/tracing/events/mmc/enable 5 adb shell echo 1 >/d/tracing/tracing_on 6 7To get the trace: 8 9 adb pull /d/tracing/trace 10 11To turn it back off, do: 12 13 adb shell echo 0 >/d/tracing/tracing_enabled 14 15The output is in a form of start/stop pairs. The ops with rw in the name are 16read or write ops, and the ones with erase in the name are the various erase 17opts. 18 19The mmc_trace_reduce script will take the output from the kernel, and convert it 20to a single line per event, which includes the duration of the event. 21 22This can then be fed into other tools for further analysis. 23 24The file mmc_trace_sample_data contains sample mmc trace data from a Nexus 10. 25It includes read, write and discard entries. The discard entries came from 26invoking fstrim in vold with "vdc fstrim dotrim". 27 28