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| author | Eric Dumazet <edumazet@google.com> | 2023-12-12 11:06:08 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-12-13 18:19:39 -0800 |
| commit | 173b6d1cdf582e7438b3ab4ef2f40e6833579490 (patch) | |
| tree | 54ce69419c7b3db30ce90bea7296d529c816b6fe /Documentation/networking/timestamping.rst | |
| parent | 85c2674d537bd8f68afa9dad49981f7e227f1131 (diff) | |
| download | linux-173b6d1cdf582e7438b3ab4ef2f40e6833579490.tar.gz linux-173b6d1cdf582e7438b3ab4ef2f40e6833579490.tar.bz2 linux-173b6d1cdf582e7438b3ab4ef2f40e6833579490.zip | |
docs: networking: timestamping: mention MSG_EOR flag
TCP got MSG_EOR support in linux-4.7.
This is a canonical way of making sure no coalescing
will be performed on the skb, even if it could not be
immediately sent.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20231212110608.3673677-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation/networking/timestamping.rst')
| -rw-r--r-- | Documentation/networking/timestamping.rst | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/Documentation/networking/timestamping.rst b/Documentation/networking/timestamping.rst index f17c01834a12..5e93cd71f99f 100644 --- a/Documentation/networking/timestamping.rst +++ b/Documentation/networking/timestamping.rst @@ -357,7 +357,8 @@ enabling SOF_TIMESTAMPING_OPT_ID and comparing the byte offset at send time with the value returned for each timestamp. It can prevent the situation by always flushing the TCP stack in between requests, for instance by enabling TCP_NODELAY and disabling TCP_CORK and -autocork. +autocork. After linux-4.7, a better way to prevent coalescing is +to use MSG_EOR flag at sendmsg() time. These precautions ensure that the timestamp is generated only when all bytes have passed a timestamp point, assuming that the network stack |