From 53025f5efd5a1c14fca75c479b11d97d9dd958a5 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Thu, 10 Jul 2008 16:47:41 -0700 Subject: Documentation: clarify tcp_{r,w}mem sysctl docs Fix some of the defaults and attempt to clarify some language. Signed-off-by: J. Bruce Fields Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 277437951e4..dc04fdd6af3 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -336,7 +336,7 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max pressure. Default: 8K - default: default size of receive buffer used by TCP sockets. + default: initial size of receive buffer used by TCP sockets. This value overrides net.core.rmem_default used by other protocols. Default: 87380 bytes. This value results in window of 65535 with default setting of tcp_adv_win_scale and tcp_app_win:0 and a bit @@ -344,8 +344,10 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max max: maximal size of receive buffer allowed for automatically selected receiver buffers for TCP socket. This value does not override - net.core.rmem_max, "static" selection via SO_RCVBUF does not use this. - Default: 87380*2 bytes. + net.core.rmem_max. Calling setsockopt() with SO_RCVBUF disables + automatic tuning of that socket's receive buffer size, in which + case this value is ignored. + Default: between 87380B and 4MB, depending on RAM size. tcp_sack - BOOLEAN Enable select acknowledgments (SACKS). @@ -419,19 +421,21 @@ tcp_window_scaling - BOOLEAN Enable window scaling as defined in RFC1323. tcp_wmem - vector of 3 INTEGERs: min, default, max - min: Amount of memory reserved for send buffers for TCP socket. + min: Amount of memory reserved for send buffers for TCP sockets. Each TCP socket has rights to use it due to fact of its birth. Default: 4K - default: Amount of memory allowed for send buffers for TCP socket - by default. This value overrides net.core.wmem_default used - by other protocols, it is usually lower than net.core.wmem_default. + default: initial size of send buffer used by TCP sockets. This + value overrides net.core.wmem_default used by other protocols. + It is usually lower than net.core.wmem_default. Default: 16K - max: Maximal amount of memory allowed for automatically selected - send buffers for TCP socket. This value does not override - net.core.wmem_max, "static" selection via SO_SNDBUF does not use this. - Default: 128K + max: Maximal amount of memory allowed for automatically tuned + send buffers for TCP sockets. This value does not override + net.core.wmem_max. Calling setsockopt() with SO_SNDBUF disables + automatic tuning of that socket's send buffer size, in which case + this value is ignored. + Default: between 64K and 4MB, depending on RAM size. tcp_workaround_signed_windows - BOOLEAN If set, assume no receipt of a window scaling option means the -- cgit v1.2.3