README
1The code in this directory is used to process data from the mmc tracepoints
2in the kernel. To turn on mmc tracing, do this:
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4 adb shell echo 1 >/d/tracing/events/mmc/enable
5 adb shell echo 1 >/d/tracing/tracing_on
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7To get the trace:
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9 adb pull /d/tracing/trace
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11To turn it back off, do:
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13 adb shell echo 0 >/d/tracing/tracing_enabled
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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.
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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.
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22This can then be fed into other tools for further analysis.
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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".
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