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jarkko

Jarkko Sakkinen

Flow planned for my cheapo #BPF flame graph for a single driver:

  1. tpm_transmit()
  2. Chop the backtrace into two pieces.
  3. Keep the top N rows, forget the the bottom.
  4. Publish N rows with 256 bytes per row room for a call entry, i.e. 0x100*N bytes to the BPF ring buffer.

The host side then consumes the fixed-size packets and puts matching stacks to the same bucket. A second thread can periodically then compose flame graph of the data corrected so far.

Somehow got into learning this eBPF stuff during the holidays :-) Super interesting and addicting.

#eBPF

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