On 07/24/2018 04:15 AM, Neal Cardwell wrote:
> On Mon, Jul 23, 2018 at 8:49 PM Lawrence Brakmo <bra...@fb.com> wrote:
>>
>> We observed high 99 and 99.9% latencies when doing RPCs with DCTCP. The
>> problem is triggered when the last packet of a request arrives CE
>> marked. The reply will carry the ECE mark causing TCP to shrink its cwnd
>> to 1 (because there are no packets in flight). When the 1st packet of
>> the next request arrives, the ACK was sometimes delayed even though it
>> is CWR marked, adding up to 40ms to the RPC latency.
>>
>> This patch insures that CWR marked data packets arriving will be acked
>> immediately.
> ...
>> Modified based on comments by Neal Cardwell <ncardw...@google.com>
>>
>> Signed-off-by: Lawrence Brakmo <bra...@fb.com>
>> ---
>>  net/ipv4/tcp_input.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> Seems like a nice mechanism to have, IMHO.
> 
> Acked-by: Neal Cardwell <ncardw...@google.com>

Should this go to net tree instead where all the other fixes went?

Thanks,
Daniel

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