Re: [net-next PATCH V5] qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE
From: Eric Dumazet <hidden>
Date: 2014-09-30 12:34:45
From: Eric Dumazet <hidden>
Date: 2014-09-30 12:34:45
On Tue, 2014-09-30 at 10:53 +0200, Jesper Dangaard Brouer wrote:
For now, as a conservative approach, don't bulk dequeue GSO and segmented GSO packets, because testing showed requeuing occuring with segmented GSO packets.
Note that GSO happens after qdisc dequeue. We should not care if part of a GSO train is stopped because TX ring is full. If we stop a GSO train, then we only lower GRO aggregation for the receiver. Normally, if BQL is properly working, we should practically not hit TX ring buffer limit, unless you send very small packets just to stress the thing (synthetic benchmark, not a real workload) We should not stop a GSO train because of BQL : Remind that BQL is to avoid head of line blocking, but there is no way another high prio packet can be sent on the wire before one if the packet resulting of GSO segments. So telling that requeueing is happening with GSO is kind of irrelevant.