Discrepancy between Inferno and flamegraph.pl CPI/IPC Output

Hello,

When generating a CPI/IPC flame graph using inferno, the output appears to be mismatch compared to the results from using Brendan Gregg's original flamegraph.pl script (https://www.brendangregg.com/blog/2014-10-31/cpi-flame-graphs.html), despite using the same input parameters.

This is output from Brendan's flamegraph.pl:

And this is from inferno's output:

**Re-creation steps:**

- using Brendan's flamegraph package:
However, with the same parameters, inferno appears giving incorrect results.
```
CONTROL_GROUP=$(systemctl show -p ControlGroup --value "${TARGET}" 2>/dev/null)
ARGS="-e cpu-cycles,instructions --call-graph dwarf,64000 -a -G $CONTROL_GROUP -- sleep $DURATION"
perf record -o "${PERF_DATA}" -z --debuginfod="${DEBUGINFOD}" ${ARGS}
perf script -i "${PERF_DATA}" 2>/dev/null > "${PERF_SCRIPT}"

/usr/local/flamegraph/stackcollapse-perf.pl --event-filter=instructions "${PERF_SCRIPT}" > "${PERF_STACKS_INSTR}"
/usr/local/flamegraph/stackcollapse-perf.pl --event-filter=cpu-cycles "${PERF_SCRIPT}" > "${PERF_STACKS_CYCLES}"

/usr/local/flamegraph/difffolded.pl "${PERF_STACKS_INSTR}" "${PERF_STACKS_CYCLES}" \
| /usr/local/flamegraph/flamegraph.pl --countname cycles \
--title "IPC Differential Flame Graph" \
--subtitle "Red: IPC < 1; White: IPC = 1; Blue: IPC > 1; color gradient show level; % scaled to TOTAL cycles" \
> "${FLAMEGRAPH_IPC_OUT}"
```

- using inferno package:

```
CONTROL_GROUP=$(systemctl show -p ControlGroup --value "${TARGET}" 2>/dev/null)
ARGS="-e cpu-cycles,instructions --call-graph dwarf,64000 -a -G $CONTROL_GROUP -- sleep $DURATION"
perf record -o "${PERF_DATA}" -z --debuginfod="${DEBUGINFOD}" ${ARGS}
perf script -i "${PERF_DATA}" 2>/dev/null > "${PERF_SCRIPT}"

/usr/bin/inferno-collapse-perf --event-filter=instructions "${PERF_SCRIPT}" > "${PERF_STACKS_INSTR}"
/usr/bin/inferno-collapse-perf --event-filter=cpu-cycles "${PERF_SCRIPT}" > "${PERF_STACKS_CYCLES}"

/usr/bin/inferno-diff-folded "${PERF_STACKS_INSTR}" "${PERF_STACKS_CYCLES}" \
| /usr/bin/inferno-flamegraph --countname cycles \
--title "IPC Differential Flame Graph" \
--subtitle "Red: IPC < 1; White: IPC = 1; Blue: IPC > 1; color gradient show level; % scaled to TOTAL cycles" \
> "${FLAMEGRAPH_IPC_OUT}"

```

inferno version: 0.12.1
flamgraph version: 2020.4.0
kernel: 6.12

Start by reproducing the supplied perf record and perf script commands, then compare inferno-collapse-perf and inferno-diff-folded with stackcollapse-perf.pl and difffolded.pl on the same input. Trace the first stage where outputs diverge; done means the discrepancy is identified and the inferno result matches the reference or the difference is explained.

Written by the indexing model from the issue text.