Re: [RFC PATCH v2 net-next 2/7] tcp: Merge tx_flags/tskey/txstamp_ack in tcp_collapse_retrans

[Martin KaFai Lau]

On Tue, Apr 19, 2016 at 10:35:52AM -0700, Eric Dumazet wrote:
> On Tue, Apr 19, 2016 at 10:28 AM, Martin KaFai Lau <ka...@fb.com> wrote:
>
> > A bit off topic, I feel like the SKBTX_ACK_TSTAMP and txstamp_ack are sort
> > of redundant but I have not look into the details yet, so not completely
> > sure.  It wwould be a separate cleanup patch if it is the case.
>
> Please read 6b084928baac562ed61866f540a96120e9c9ddb7 changelog ;)
>
> A cache line miss avoidance is critical
I looked at the patch but I probably am missing something :(
Is checking txstamp_ack alone enough and SKBTX_ACK_TSTAMP is not needed
since they are always set together?