AuxXxilium/linux_dsm_epyc7002
1
0
Fork 0
mirror of https://github.com/AuxXxilium/linux_dsm_epyc7002.git synced 2024-12-25 10:23:55 +07:00
Code Issues Actions Packages Projects Releases Wiki Activity
0ab2e55d33
linux_dsm_epyc7002/net/core
History
Eric Dumazet 218af599fa tcp: internal implementation for pacing 
BBR congestion control depends on pacing, and pacing is
currently handled by sch_fq packet scheduler for performance reasons,
and also because implemening pacing with FQ was convenient to truly
avoid bursts.

However there are many cases where this packet scheduler constraint
is not practical.
- Many linux hosts are not focusing on handling thousands of TCP
  flows in the most efficient way.
- Some routers use fq_codel or other AQM, but still would like
  to use BBR for the few TCP flows they initiate/terminate.

This patch implements an automatic fallback to internal pacing.

Pacing is requested either by BBR or use of SO_MAX_PACING_RATE option.

If sch_fq happens to be in the egress path, pacing is delegated to
the qdisc, otherwise pacing is done by TCP itself.

One advantage of pacing from TCP stack is to get more precise rtt
estimations, and less work done from TX completion, since TCP Small
queue limits are not generally hit. Setups with single TX queue but
many cpus might even benefit from this.

Note that unlike sch_fq, we do not take into account header sizes.
Taking care of these headers would add additional complexity for
no practical differences in behavior.

Some performance numbers using 800 TCP_STREAM flows rate limited to
~48 Mbit per second on 40Gbit NIC.

If MQ+pfifo_fast is used on the NIC :

$ sar -n DEV 1 5 | grep eth
14:48:44         eth0 725743.00 2932134.00  46776.76 4335184.68      0.00      0.00      1.00
14:48:45         eth0 725349.00 2932112.00  46751.86 4335158.90      0.00      0.00      0.00
14:48:46         eth0 725101.00 2931153.00  46735.07 4333748.63      0.00      0.00      0.00
14:48:47         eth0 725099.00 2931161.00  46735.11 4333760.44      0.00      0.00      1.00
14:48:48         eth0 725160.00 2931731.00  46738.88 4334606.07      0.00      0.00      0.00
Average:         eth0 725290.40 2931658.20  46747.54 4334491.74      0.00      0.00      0.40
$ vmstat 1 5
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 4  0      0 259825920  45644 2708324    0    0    21     2  247   98  0  0 100  0  0
 4  0      0 259823744  45644 2708356    0    0     0     0 2400825 159843  0 19 81  0  0
 0  0      0 259824208  45644 2708072    0    0     0     0 2407351 159929  0 19 81  0  0
 1  0      0 259824592  45644 2708128    0    0     0     0 2405183 160386  0 19 80  0  0
 1  0      0 259824272  45644 2707868    0    0     0    32 2396361 158037  0 19 81  0  0

Now use MQ+FQ :

lpaa23:~# echo fq >/proc/sys/net/core/default_qdisc
lpaa23:~# tc qdisc replace dev eth0 root mq

$ sar -n DEV 1 5 | grep eth
14:49:57         eth0 678614.00 2727930.00  43739.13 4033279.14      0.00      0.00      0.00
14:49:58         eth0 677620.00 2723971.00  43674.69 4027429.62      0.00      0.00      1.00
14:49:59         eth0 676396.00 2719050.00  43596.83 4020125.02      0.00      0.00      0.00
14:50:00         eth0 675197.00 2714173.00  43518.62 4012938.90      0.00      0.00      1.00
14:50:01         eth0 676388.00 2719063.00  43595.47 4020171.64      0.00      0.00      0.00
Average:         eth0 676843.00 2720837.40  43624.95 4022788.86      0.00      0.00      0.40
$ vmstat 1 5
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 2  0      0 259832240  46008 2710912    0    0    21     2  223  192  0  1 99  0  0
 1  0      0 259832896  46008 2710744    0    0     0     0 1702206 198078  0 17 82  0  0
 0  0      0 259830272  46008 2710596    0    0     0     0 1696340 197756  1 17 83  0  0
 4  0      0 259829168  46024 2710584    0    0    16     0 1688472 197158  1 17 82  0  0
 3  0      0 259830224  46024 2710408    0    0     0     0 1692450 197212  0 18 82  0  0

As expected, number of interrupts per second is very different.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Van Jacobson <vanj@google.com>
Cc: Jerry Chu <hkchu@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-16 15:43:31 -04:00
..
datagram.c net/sock: factor out dequeue/peek with offset code 2017-05-16 15:41:29 -04:00
dev_addr_lists.c
dev_ioctl.c
dev.c xdp: refine xdp api with regards to generic xdp 2017-05-11 21:30:57 -04:00
devlink.c net/devlink: Add E-Switch encapsulation control 2017-04-22 20:26:37 +03:00
drop_monitor.c drop_monitor: use setup_timer 2017-03-12 23:47:16 -07:00
dst_cache.c
dst.c net: pending_confirm is not used anymore 2017-02-07 13:07:47 -05:00
ethtool.c net: Add ESP offload features 2017-04-14 10:05:36 +02:00
fib_rules.c fib_rules: fix error return code 2017-04-27 16:35:57 -04:00
filter.c bpf: restore skb->sk before pskb_trim() call 2017-04-30 22:23:16 -04:00
flow_dissector.c flow_dissector: add mpls support (v2) 2017-04-24 14:30:46 -04:00
flow.c flowcache: more "unsigned int" 2017-04-03 19:04:48 -07:00
gen_estimator.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
gen_stats.c net_sched: gen_estimator: complete rewrite of rate estimators 2016-12-05 15:21:59 -05:00
gro_cells.c net: Generic XDP 2017-04-25 13:33:49 -04:00
hwbm.c
link_watch.c
lwt_bpf.c netlink: pass extended ACK struct to parsing functions 2017-04-13 13:58:22 -04:00
lwtunnel.c lwtunnel: fix error path in lwtunnel_fill_encap() 2017-04-30 22:41:29 -04:00
Makefile gro_cells: move to net/core/gro_cells.c 2017-02-08 14:38:18 -05:00
neighbour.c net: rtnetlink: plumb extended ack to doit function 2017-04-17 15:35:38 -04:00
net_namespace.c net: Initialise init_net.count to 1 2017-04-30 22:32:16 -04:00
net-procfs.c
net-sysfs.c net: use net->count to check whether a netns is alive or not 2017-03-13 16:02:27 -07:00
net-sysfs.h
net-traces.c
netclassid_cgroup.c cgroup, net_cls: iterate the fds of only the tasks which are being migrated 2017-03-22 10:32:46 -07:00
netevent.c
netpoll.c netpoll: Check for skb->queue_mapping 2017-04-21 15:45:19 -04:00
netprio_cgroup.c net: break include loop netdevice.h, dsa.h, devlink.h 2017-03-28 22:46:04 -07:00
pktgen.c net-tc: convert tc_verd to integer bitfields 2017-01-08 20:58:52 -05:00
ptp_classifier.c
request_sock.c ipv4: Namespaceify tcp_max_syn_backlog knob 2016-12-29 11:38:31 -05:00
rtnetlink.c xdp: refine xdp api with regards to generic xdp 2017-05-11 21:30:57 -04:00
scm.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/user.h> 2017-03-02 08:42:29 +01:00
secure_seq.c tcp: randomize timestamps on syncookies 2017-05-05 12:00:11 -04:00
skbuff.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-05-02 16:40:27 -07:00
sock_diag.c netlink: extended ACK reporting 2017-04-13 13:58:20 -04:00
sock_reuseport.c soreuseport: use "unsigned int" in __reuseport_alloc() 2017-04-03 19:06:38 -07:00
sock.c tcp: internal implementation for pacing 2017-05-16 15:43:31 -04:00
stream.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
sysctl_net_core.c Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning 2017-04-21 13:22:34 -04:00
timestamping.c
tso.c
utils.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-05-02 16:40:27 -07:00