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500f808726
Currently OVS uses jhash2() for calculating flow hashes in its internal flow_hash() function. The performance of the flow_hash() function is critical, as the input data can be hundreds of bytes long. OVS is largely deployed in x86_64 based datacenters. Therefore, we argue that the performance critical fast path of OVS should exploit underlying CPU features in order to reduce the per packet processing costs. We replace jhash2 with the hash implementation provided by the kernel hash lib, which exploits the crc32l instruction to achieve high performance Our patch greatly reduces the hash footprint from ~200 cycles of jhash2() to around ~90 cycles in case of ovs_flow_hash_crc() (measured with rdtsc over maximum length flow keys on an i7 Intel CPU). Additionally, we wrote a microbenchmark to stress the flow table performance. The benchmark inserts random flows into the flow hash and then performs lookups. Our hash deployed on a CRC32 capable CPU reduces the lookup for 1000 flows, 100 masks from ~10,100us to ~6,700us, for example. Thus, simply use the newly introduced arch_fast_hash2() as a drop-in replacement. Signed-off-by: Francesco Fusco <ffusco@redhat.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Thomas Graf <tgraf@redhat.com> Acked-by: Jesse Gross <jesse@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| actions.c | ||
| datapath.c | ||
| datapath.h | ||
| dp_notify.c | ||
| flow.c | ||
| flow.h | ||
| flow_netlink.c | ||
| flow_netlink.h | ||
| flow_table.c | ||
| flow_table.h | ||
| Kconfig | ||
| Makefile | ||
| vport-gre.c | ||
| vport-internal_dev.c | ||
| vport-internal_dev.h | ||
| vport-netdev.c | ||
| vport-netdev.h | ||
| vport-vxlan.c | ||
| vport.c | ||
| vport.h | ||