--- zzzz-none-000/linux-3.10.107/Documentation/sysctl/net.txt 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/Documentation/sysctl/net.txt 2021-02-04 17:41:59.000000000 +0000 @@ -1,4 +1,4 @@ -Documentation for /proc/sys/net/* kernel version 2.4.0-test11-pre4 +Documentation for /proc/sys/net/* (c) 1999 Terrehon Bowden Bodo Bauer (c) 2000 Jorge Nerin @@ -9,10 +9,10 @@ ============================================================== This file contains the documentation for the sysctl files in -/proc/sys/net and is valid for Linux kernel version 2.4.0-test11-pre4. +/proc/sys/net The interface to the networking parts of the kernel is located in -/proc/sys/net. The following table shows all possible subdirectories.You may +/proc/sys/net. The following table shows all possible subdirectories. You may see only some of them, depending on your kernel's configuration. @@ -26,7 +26,7 @@ ipv4 IP version 4 x25 X.25 protocol ipx IPX token-ring IBM token ring bridge Bridging decnet DEC net - ipv6 IP version 6 + ipv6 IP version 6 tipc TIPC .............................................................................. 1. /proc/sys/net/core - Network core options @@ -50,6 +50,45 @@ it's a Per-CPU variable. Default: 64 +default_qdisc +-------------- + +The default queuing discipline to use for network devices. This allows +overriding the default of pfifo_fast with an alternative. Since the default +queuing discipline is created without additional parameters so is best suited +to queuing disciplines that work well without configuration like stochastic +fair queue (sfq), CoDel (codel) or fair queue CoDel (fq_codel). Don't use +queuing disciplines like Hierarchical Token Bucket or Deficit Round Robin +which require setting up classes and bandwidths. Note that physical multiqueue +interfaces still use mq as root qdisc, which in turn uses this default for its +leaves. Virtual devices (like e.g. lo or veth) ignore this setting and instead +default to noqueue. +Default: pfifo_fast + +busy_read +---------------- +Low latency busy poll timeout for socket reads. (needs CONFIG_NET_RX_BUSY_POLL) +Approximate time in us to busy loop waiting for packets on the device queue. +This sets the default value of the SO_BUSY_POLL socket option. +Can be set or overridden per socket by setting socket option SO_BUSY_POLL, +which is the preferred method of enabling. If you need to enable the feature +globally via sysctl, a value of 50 is recommended. +Will increase power usage. +Default: 0 (off) + +busy_poll +---------------- +Low latency busy poll timeout for poll and select. (needs CONFIG_NET_RX_BUSY_POLL) +Approximate time in us to busy loop waiting for events. +Recommended value depends on the number of sockets you poll on. +For several sockets 50, for several hundreds 100. +For more than that you probably want to use epoll. +Note that only sockets with SO_BUSY_POLL set will be busy polled, +so you want to either selectively set SO_BUSY_POLL on those sockets or set +sysctl.net.busy_read globally. +Will increase power usage. +Default: 0 (off) + rmem_default ------------ @@ -60,6 +99,14 @@ The maximum receive socket buffer size in bytes. +tstamp_allow_data +----------------- +Allow processes to receive tx timestamps looped together with the original +packet contents. If disabled, transmit timestamp requests from unprivileged +processes are dropped unless socket option SOF_TIMESTAMPING_OPT_TSONLY is set. +Default: 1 (on) + + wmem_default ------------ @@ -83,18 +130,21 @@ warnings -------- -This controls console messages from the networking stack that can occur because -of problems on the network like duplicate address or bad checksums. Normally, -this should be enabled, but if the problem persists the messages can be -disabled. +This sysctl is now unused. + +This was used to control console messages from the networking stack that +occur because of problems on the network like duplicate address or bad +checksums. + +These messages are now emitted at KERN_DEBUG and can generally be enabled +and controlled by the dynamic_debug facility. netdev_budget ------------- Maximum number of packets taken from all interfaces in one polling cycle (NAPI poll). In one polling cycle interfaces which are registered to polling are -probed in a round-robin manner. The limit of packets in one such probe can be -set per-device via sysfs class/net//weight . +probed in a round-robin manner. netdev_max_backlog ------------------ @@ -102,6 +152,28 @@ Maximum number of packets, queued on the INPUT side, when the interface receives packets faster than kernel can process them. +netdev_rss_key +-------------- + +RSS (Receive Side Scaling) enabled drivers use a 40 bytes host key that is +randomly generated. +Some user space might need to gather its content even if drivers do not +provide ethtool -x support yet. + +myhost:~# cat /proc/sys/net/core/netdev_rss_key +84:50:f4:00:a8:15:d1:a7:e9:7f:1d:60:35:c7:47:25:42:97:74:ca:56:bb:b6:a1:d8: ... (52 bytes total) + +File contains nul bytes if no driver ever called netdev_rss_key_fill() function. +Note: +/proc/sys/net/core/netdev_rss_key contains 52 bytes of key, +but most drivers only use 40 bytes of it. + +myhost:~# ethtool -x eth0 +RX flow hash indirection table for eth0 with 8 RX ring(s): + 0: 0 1 2 3 4 5 6 7 +RSS hash key: +84:50:f4:00:a8:15:d1:a7:e9:7f:1d:60:35:c7:47:25:42:97:74:ca:56:bb:b6:a1:d8:43:e3:c9:0c:fd:17:55:c2:3a:4d:69:ed:f1:42:89 + netdev_tstamp_prequeue ---------------------- @@ -201,3 +273,34 @@ The /proc/net/ipx_route table holds a list of IPX routes. For each route it gives the destination network, the router node (or Directly) and the network address of the router (or Connected) for internal networks. + +6. TIPC +------------------------------------------------------- + +tipc_rmem +---------- + +The TIPC protocol now has a tunable for the receive memory, similar to the +tcp_rmem - i.e. a vector of 3 INTEGERs: (min, default, max) + + # cat /proc/sys/net/tipc/tipc_rmem + 4252725 34021800 68043600 + # + +The max value is set to CONN_OVERLOAD_LIMIT, and the default and min values +are scaled (shifted) versions of that same value. Note that the min value +is not at this point in time used in any meaningful way, but the triplet is +preserved in order to be consistent with things like tcp_rmem. + +named_timeout +-------------- + +TIPC name table updates are distributed asynchronously in a cluster, without +any form of transaction handling. This means that different race scenarios are +possible. One such is that a name withdrawal sent out by one node and received +by another node may arrive after a second, overlapping name publication already +has been accepted from a third node, although the conflicting updates +originally may have been issued in the correct sequential order. +If named_timeout is nonzero, failed topology updates will be placed on a defer +queue until another event arrives that clears the error, or until the timeout +expires. Value is in milliseconds.