diff options
Diffstat (limited to 'Documentation/sysctl')
| -rw-r--r-- | Documentation/sysctl/net.txt | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/Documentation/sysctl/net.txt b/Documentation/sysctl/net.txt index 5369879eafe2..e658bbfb641f 100644 --- a/Documentation/sysctl/net.txt +++ b/Documentation/sysctl/net.txt @@ -50,13 +50,27 @@ The maximum number of packets that kernel can handle on a NAPI interrupt, it's a Per-CPU variable. Default: 64 -low_latency_poll +low_latency_read ---------------- -Low latency busy poll timeout. (needs CONFIG_NET_LL_RX_POLL) +Low latency busy poll timeout for socket reads. (needs CONFIG_NET_LL_RX_POLL) Approximate time in us to spin waiting for packets on the device queue. +This sets the default value of the SO_LL socket option. +Can be set or overridden per socket by setting socket option SO_LL. Recommended value is 50. May increase power usage. Default: 0 (off) +low_latency_poll +---------------- +Low latency busy poll timeout for poll and select. (needs CONFIG_NET_LL_RX_POLL) +Approximate time in us to spin waiting for packets on the device queue. +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_LL set will be busy polled, so you want to either +selectively set SO_LL on those sockets or set sysctl.net.low_latency_read globally. +May increase power usage. +Default: 0 (off) + rmem_default ------------ |