mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-27 22:51:31 +00:00
046e1537a3
Network drivers can call to netif_get_num_default_rss_queues to get the default number of receive queues to use. Right now, this default number is min(8, num_online_cpus()). Instead, as suggested by Jakub, use the number of physical cores divided by 2 as a way to avoid wasting CPU resources and to avoid using both CPU threads, but still allowing to scale for high-end processors with many cores. As an exception, select 2 queues for processors with 2 cores, because otherwise it won't take any advantage of RSS despite being SMP capable. Tested: Processor Intel Xeon E5-2620 (2 sockets, 6 cores/socket, 2 threads/core). NIC Broadcom NetXtreme II BCM57810 (10GBps). Ran some tests with `perf stat iperf3 -R`, with parallelisms of 1, 8 and 24, getting the following results: - Number of queues: 6 (instead of 8) - Network throughput: not affected - CPU usage: utilized 0.05-0.12 CPUs more than before (having 24 CPUs this is only 0.2-0.5% higher) - Reduced the number of context switches by 7-50%, being more noticeable when using a higher number of parallel threads. Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Íñigo Huguet <ihuguet@redhat.com> Link: https://lore.kernel.org/r/20220315091832.13873-1-ihuguet@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
||
---|---|---|
.. | ||
bpf_sk_storage.c | ||
datagram.c | ||
datagram.h | ||
dev.c | ||
dev_addr_lists.c | ||
dev_addr_lists_test.c | ||
dev_ioctl.c | ||
devlink.c | ||
drop_monitor.c | ||
dst.c | ||
dst_cache.c | ||
failover.c | ||
fib_notifier.c | ||
fib_rules.c | ||
filter.c | ||
flow_dissector.c | ||
flow_offload.c | ||
gen_estimator.c | ||
gen_stats.c | ||
gro.c | ||
gro_cells.c | ||
hwbm.c | ||
link_watch.c | ||
lwt_bpf.c | ||
lwtunnel.c | ||
Makefile | ||
neighbour.c | ||
net-procfs.c | ||
net-sysfs.c | ||
net-sysfs.h | ||
net-traces.c | ||
net_namespace.c | ||
netclassid_cgroup.c | ||
netevent.c | ||
netpoll.c | ||
netprio_cgroup.c | ||
of_net.c | ||
page_pool.c | ||
pktgen.c | ||
ptp_classifier.c | ||
request_sock.c | ||
rtnetlink.c | ||
scm.c | ||
secure_seq.c | ||
selftests.c | ||
skbuff.c | ||
skmsg.c | ||
sock.c | ||
sock_destructor.h | ||
sock_diag.c | ||
sock_map.c | ||
sock_reuseport.c | ||
stream.c | ||
sysctl_net_core.c | ||
timestamping.c | ||
tso.c | ||
utils.c | ||
xdp.c |