1.. SPDX-License-Identifier: GPL-2.0
2
3==========
4SMC Sysctl
5==========
6
7/proc/sys/net/smc/* Variables
8=============================
9
10autocorking_size - INTEGER
11	Setting SMC auto corking size:
12	SMC auto corking is like TCP auto corking from the application's
13	perspective of view. When applications do consecutive small
14	write()/sendmsg() system calls, we try to coalesce these small writes
15	as much as possible, to lower total amount of CDC and RDMA Write been
16	sent.
17	autocorking_size limits the maximum corked bytes that can be sent to
18	the under device in 1 single sending. If set to 0, the SMC auto corking
19	is disabled.
20	Applications can still use TCP_CORK for optimal behavior when they
21	know how/when to uncork their sockets.
22
23	Default: 64K
24
25smcr_buf_type - INTEGER
26        Controls which type of sndbufs and RMBs to use in later newly created
27        SMC-R link group. Only for SMC-R.
28
29        Default: 0 (physically contiguous sndbufs and RMBs)
30
31        Possible values:
32
33        - 0 - Use physically contiguous buffers
34        - 1 - Use virtually contiguous buffers
35        - 2 - Mixed use of the two types. Try physically contiguous buffers first.
36          If not available, use virtually contiguous buffers then.
37
38smcr_testlink_time - INTEGER
39	How frequently SMC-R link sends out TEST_LINK LLC messages to confirm
40	viability, after the last activity of connections on it. Value 0 means
41	disabling TEST_LINK.
42
43	Default: 30 seconds.
44
45wmem - INTEGER
46	Initial size of send buffer used by SMC sockets.
47	The default value inherits from net.ipv4.tcp_wmem[1].
48
49	The minimum value is 16KiB and there is no hard limit for max value, but
50	only allowed 512KiB for SMC-R and 1MiB for SMC-D.
51
52	Default: 16K
53
54rmem - INTEGER
55	Initial size of receive buffer (RMB) used by SMC sockets.
56	The default value inherits from net.ipv4.tcp_rmem[1].
57
58	The minimum value is 16KiB and there is no hard limit for max value, but
59	only allowed 512KiB for SMC-R and 1MiB for SMC-D.
60
61	Default: 128K
62