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qlxge(4): Distribute RSS over num_rx_rings with a modulo
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Authored by nick_spun.io on Tue, May 26, 5:02 PM.
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Details

Reviewers
adrian
Summary

qls_init_rss() built the RSS indirection table with rss_icb->cq_id[i] = (i & (ha->num_rx_rings - 1)); which assumes num_rx_rings is a power of two. When it is not, the AND mask leaves some completion queues with no entries and skews the hash
distribution.

MAX_RX_RINGS is currently hardcoded to 1, so this is latent today, but use a modulo so the table stays correct if the ring count is ever raised to a non-power-of-two value.

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Repository
rG FreeBSD src repository
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Unit
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Build Status
Buildable 73456
Build 70339: arc lint + arc unit