Function custom_cache_pipe_io_compute_imbalance 

pub fn custom_cache_pipe_io_compute_imbalance(
    ctx: &Ctx<'_>,
) -> Result<AssertResult>

CachePipe vs SpinWait cgroups under work conservation.

One cgroup runs CachePipe workers (cache-hot burst then pipe exchange, combining cache pressure with cross-CPU wake placement). The other runs SpinWait at full CPU count. Checks wake latency CV to catch erratic pipe wake placement.