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authorLukas Larsson <[email protected]>2018-06-21 11:00:25 +0200
committerLukas Larsson <[email protected]>2018-07-30 16:55:26 +0200
commita9d361b4be7d6329bedd7b37d454c1abf4f27233 (patch)
treea55a060d66bad33cff29fe00ab1ac1b171a4ce74 /lib/kernel/doc/src
parent83445d0de88a1ad15066e6c415b2c2d9aa93d6a1 (diff)
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erts: Limit the automatic max buffer for UDP to 2^16
There is no reason to have a larger buffer than this as the recvmsg call will never return more data. OTP-15206
Diffstat (limited to 'lib/kernel/doc/src')
-rw-r--r--lib/kernel/doc/src/inet.xml19
1 files changed, 10 insertions, 9 deletions
diff --git a/lib/kernel/doc/src/inet.xml b/lib/kernel/doc/src/inet.xml
index e6a7962c5a..f281d61459 100644
--- a/lib/kernel/doc/src/inet.xml
+++ b/lib/kernel/doc/src/inet.xml
@@ -734,22 +734,23 @@ get_tcpi_sacked(Sock) ->
</item>
<tag><c>{buffer, Size}</c></tag>
<item>
- <p>The size of the user-level software buffer used by
- the driver.
- Not to be confused with options <c>sndbuf</c>
+ <p>The size of the user-level buffer used by
+ the driver. Not to be confused with options <c>sndbuf</c>
and <c>recbuf</c>, which correspond to the
- Kernel socket buffers. It is recommended
- to have <c>val(buffer) &gt;= max(val(sndbuf),val(recbuf))</c> to
+ Kernel socket buffers. For TCP it is recommended
+ to have <c>val(buffer) &gt;= val(recbuf)</c> to
avoid performance issues because of unnecessary copying.
+ For UDP the same recommendation applies, but the max should
+ not be larger than the MTU of the network path.
<c>val(buffer)</c> is automatically set to the above
- maximum when values <c>sndbuf</c> or <c>recbuf</c> are set.
- However, as the sizes set for <c>sndbuf</c> and <c>recbuf</c>
+ maximum when <c>recbuf</c> is set.
+ However, as the size set for <c>recbuf</c>
usually become larger, you are encouraged to use
<seealso marker="#getopts/2"><c>getopts/2</c></seealso>
to analyze the behavior of your operating system.</p>
<p>Note that this is also the maximum amount of data that can be
- received from a single recv call. If you are using higher than
- normal MTU consider setting buffer higher.</p>
+ received from a single recv call. If you are using higher than
+ normal MTU consider setting buffer higher.</p>
</item>
<tag><c>{delay_send, Boolean}</c></tag>
<item>