tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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