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The code in this directory is used to process data from the mmc tracepoints
in the kernel. To turn on mmc tracing, do this:
adb shell echo 1 >/d/tracing/events/mmc/enable
adb shell echo 1 >/d/tracing/tracing_on
To get the trace:
adb pull /d/tracing/trace
To turn it back off, do:
adb shell echo 0 >/d/tracing/tracing_enabled
The output is in a form of start/stop pairs. The ops with rw in the name are
read or write ops, and the ones with erase in the name are the various erase
The mmc_trace_reduce script will take the output from the kernel, and convert it
to a single line per event, which includes the duration of the event.
This can then be fed into other tools for further analysis.
The file mmc_trace_sample_data contains sample mmc trace data from a Nexus 10.
It includes read, write and discard entries. The discard entries came from
invoking fstrim in vold with "vdc fstrim dotrim".