This patch series is aimed at improving xmit performances of lockless qdisc
in the uncontended scenario.
After the lockless refactor pfifo_fast can't leverage the BYPASS optimization.
Due to retpolines the overhead for the avoidables enqueue and dequeue operations
has increased and we see measurable regressions.
The first patch introduces the BYPASS code path for lockless qdisc, and the
second one optimizes such path further. Overall this avoids up to 3 indirect
calls per xmit packet. Detailed performance figures are reported in the 2nd
patch.
v1 -> v2:
- use really an 'empty' flag instead of 'not_empty', as
suggested by Eric
Paolo Abeni (2):
net: sched: add empty status flag for NOLOCK qdisc
net: dev: introduce support for sch BYPASS for lockless qdisc
include/net/sch_generic.h | 11 +++++++++++
net/core/dev.c | 9 +++++++++
net/sched/sch_generic.c | 3 +++
3 files changed, 23 insertions(+)
--
2.20.1
