Eric Dumazet 9d18562a22 fq_codel: add batch ability to fq_codel_drop() ... In presence of inelastic flows and stress, we can call fq_codel_drop() for every packet entering fq_codel qdisc. fq_codel_drop() is quite expensive, as it does a linear scan of 4 KB of memory to find a fat flow. Once found, it drops the oldest packet of this flow. Instead of dropping a single packet, try to drop 50% of the backlog of this fat flow, with a configurable limit of 64 packets per round. TCA_FQ_CODEL_DROP_BATCH_SIZE is the new attribute to make this limit configurable. With this strategy the 4 KB search is amortized to a single cache line per drop [1], so fq_codel_drop() no longer appears at the top of kernel profile in presence of few inelastic flows. [1] Assuming a 64byte cache line, and 1024 buckets Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dave Taht <dave.taht@gmail.com> Cc: Jonathan Morton <chromatix99@gmail.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Dave Taht Signed-off-by: David S. Miller <davem@davemloft.net>		2016-05-03 12:47:09 -04:00
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asm-generic	generic syscalls: wire up preadv2 and pwritev2 syscalls	2016-04-23 22:38:08 +02:00
drm
linux	fq_codel: add batch ability to fq_codel_drop()	2016-05-03 12:47:09 -04:00
misc
mtd
rdma	Merge branches 'i40iw', 'sriov' and 'hfi1' into k.o/for-4.6	2016-03-21 17:32:23 -04:00
scsi
sound
video
xen
Kbuild