On Tue, 3 Mar 2026 19:15:33 +0100 Björn Töpel wrote:
> +def _require_dynamic_indir_size(cfg, ch_max):
> + """Skip if the device does not dynamically size its indirection table."""
> + ethtool(f"-X {cfg.ifname} default")
> + ethtool(f"-L {cfg.ifname} combined 2")
> + small = len(_get_rss(cfg)['rss-indirection-table'])
> + ethtool(f"-L {cfg.ifname} combined {ch_max}")
> + large = len(_get_rss(cfg)['rss-indirection-table'])
> +
> + if small == large:
> + raise KsftSkipEx("Device does not dynamically size indirection
> table")
> +
> +
> @ksft_variants([
> KsftNamedVariant("main", False),
> KsftNamedVariant("ctx", True),
> @@ -76,11 +88,90 @@ def indir_size_4x(cfg, create_context):
> _test_rss_indir_size(cfg, test_max, context=ctx_id)
>
>
> +@ksft_variants([
> + KsftNamedVariant("main", False),
> + KsftNamedVariant("ctx", True),
> +])
> +def resize_periodic(cfg, create_context):
> + """Test that a periodic indirection table survives channel changes.
> +
> + Set a periodic table (equal 2), reduce channels to trigger a
> + fold, then increase to trigger an unfold. Verify the table pattern
> + is preserved and the size tracks the channel count.
> + """
> + channels = cfg.ethnl.channels_get({'header': {'dev-index': cfg.ifindex}})
> + ch_max = channels.get('combined-max', 0)
> + qcnt = channels['combined-count']
> +
> + if ch_max < 4:
> + raise KsftSkipEx(f"Not enough queues for the test: max={ch_max}")
> +
> + defer(ethtool, f"-L {cfg.ifname} combined {qcnt}")
> + ethtool(f"-L {cfg.ifname} combined {ch_max}")
> +
> + _require_dynamic_indir_size(cfg, ch_max)
> +
> + ctx_id = _maybe_create_context(cfg, create_context)
> + ctx_ref = f"context {ctx_id}" if ctx_id else ""
> +
> + ethtool(f"-X {cfg.ifname} {ctx_ref} equal 2")
> + if not create_context:
> + defer(ethtool, f"-X {cfg.ifname} default")
> +
> + orig_size = len(_get_rss(cfg, context=ctx_id)['rss-indirection-table'])
> +
> + # Shrink — should fold
> + ethtool(f"-L {cfg.ifname} combined 2")
I wonder if we may miss some cases because we init the table to [0, 1]
and also only enable only 2 queues. Let's set it to 4 queues here to
potentially catch the driver resetting the table? 2 vs 4 are both tiny
values.
Alternatively we could use netlink to set the inidir table as
[1, 0] x N
rather than
[0, 1] x N
and..
> + rss = _get_rss(cfg, context=ctx_id)
> + indir = rss['rss-indirection-table']
> +
> + ksft_ge(orig_size, len(indir), "Table did not shrink")
> + ksft_eq(set(indir), {0, 1}, "Folded table has wrong queues")
here actually check
ksft_eq(indir, [1, 0] * (len / 2), "Folded table has wrong queues")
> + # Grow back — should unfold
> + ethtool(f"-L {cfg.ifname} combined {ch_max}")
> + rss = _get_rss(cfg, context=ctx_id)
> + indir = rss['rss-indirection-table']
> +
> + ksft_eq(len(indir), orig_size, "Table size not restored")
> + ksft_eq(set(indir), {0, 1}, "Unfolded table has wrong queues")
> +
> +
> +def resize_nonperiodic_reject(cfg):
> + """Test that a non-periodic table blocks channel reduction.
> +
> + Set equal weight across all queues so the table is not periodic
> + at any smaller size, then verify channel reduction is rejected.
> + """
> + channels = cfg.ethnl.channels_get({'header': {'dev-index': cfg.ifindex}})
> + ch_max = channels.get('combined-max', 0)
> + qcnt = channels['combined-count']
> +
> + if ch_max < 4:
> + raise KsftSkipEx(f"Not enough queues for the test: max={ch_max}")
> +
> + defer(ethtool, f"-L {cfg.ifname} combined {qcnt}")
> + ethtool(f"-L {cfg.ifname} combined {ch_max}")
> +
> + _require_dynamic_indir_size(cfg, ch_max)
> +
> + ethtool(f"-X {cfg.ifname} equal {ch_max}")
> + defer(ethtool, f"-X {cfg.ifname} default")
> +
> + try:
> + ethtool(f"-L {cfg.ifname} combined 2")
> + except CmdExitFailure:
> + pass
> + else:
> + raise KsftFailEx("Channel reduction should fail with non-periodic
> table")
grep for ksft_raises()
> def main() -> None:
> """ Ksft boiler plate main """
> - with NetDrvEnv(__file__) as cfg:
> + with NetDrvEnv(__file__, queue_count=8) as cfg:
the queue_count=8 presumably only applies to netdevsim so it should go
> cfg.ethnl = EthtoolFamily()
> - ksft_run([indir_size_4x], args=(cfg, ))
> + ksft_run([indir_size_4x, resize_periodic,
> + resize_nonperiodic_reject], args=(cfg, ))
> ksft_exit()
>
>
