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由 Marcin Wojtas 提交于
Tests showed that when whole bandwidth is consumed, the latency for various kind of traffic can reach high values. With saturated link (e.g. with iperf from target to host) simple ping could take significant amount of time. BQL proved to improve this situation when implemented in mvneta driver. Measurements of ping latency for 3 link speeds: Speed | Latency w/o BQL | Latency with BQL 10 | 7-14 ms | 3.5 ms 100 | 2-12 ms | 0.6 ms 1000 | often timeout | up to 2ms Decreasing latency as above result in sligt performance cost - 4kpps (-1.4%) when pushing 64B packets via two bridged interfaces of Armada 38x. For 1500B packets in the same setup, the mpstat tool showed +8% of CPU occupation (default affinity, second CPU idle). Even though this cost seems reasonable to take, considering other improvements. This commit adds byte queue limit mechanism for the mvneta driver. Signed-off-by: NMarcin Wojtas <mw@semihalf.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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