SMC Sysctl¶
/proc/sys/net/smc/* Variables¶
- autocorking_size - INTEGER
- Setting SMC auto corking size: SMC auto corking is like TCP auto corking from the application’s perspective of view. When applications do consecutive small write()/sendmsg() system calls, we try to coalesce these small writes as much as possible, to lower total amount of CDC and RDMA Write been sent. autocorking_size limits the maximum corked bytes that can be sent to the under device in 1 single sending. If set to 0, the SMC auto corking is disabled. Applications can still use TCP_CORK for optimal behavior when they know how/when to uncork their sockets. - Default: 64K 
- smcr_buf_type - INTEGER
- Controls which type of sndbufs and RMBs to use in later newly created SMC-R link group. Only for SMC-R. - Default: 0 (physically contiguous sndbufs and RMBs) - Possible values: - 0 - Use physically contiguous buffers 
- 1 - Use virtually contiguous buffers 
- 2 - Mixed use of the two types. Try physically contiguous buffers first. If not available, use virtually contiguous buffers then. 
 
- smcr_testlink_time - INTEGER
- How frequently SMC-R link sends out TEST_LINK LLC messages to confirm viability, after the last activity of connections on it. Value 0 means disabling TEST_LINK. - Default: 30 seconds. 
- wmem - INTEGER
- Initial size of send buffer used by SMC sockets. - The minimum value is 16KiB and there is no hard limit for max value, but only allowed 512KiB for SMC-R and 1MiB for SMC-D. - Default: 64KiB 
- rmem - INTEGER
- Initial size of receive buffer (RMB) used by SMC sockets. - The minimum value is 16KiB and there is no hard limit for max value, but only allowed 512KiB for SMC-R and 1MiB for SMC-D. - Default: 64KiB 
- smcr_max_links_per_lgr - INTEGER
- Controls the max number of links can be added to a SMC-R link group. Notice that the actual number of the links added to a SMC-R link group depends on the number of RDMA devices exist in the system. The acceptable value ranges from 1 to 2. Only for SMC-R v2.1 and later. - Default: 2 
- smcr_max_conns_per_lgr - INTEGER
- Controls the max number of connections can be added to a SMC-R link group. The acceptable value ranges from 16 to 255. Only for SMC-R v2.1 and later. - Default: 255