[PATCH 0/3][j/l/m linux-azure] Azure: Improve SQL DB latency

[Tim Gardner]

BugLink: https://bugs.launchpad.net/bugs/2040300

SRU Justification

[Impact]

TCP pingpong threshold is 1 by default. But some applications, like SQL DB
may prefer a higher pingpong threshold to activate delayed acks in quick
ack mode for better performance.

There is no single value that fits all applications.
Add net.ipv4.tcp_pingpong_thresh sysctl tunable, so it can be tuned for
optimal performance based on the application needs.

[Test Case]

Microsoft tested

[Regression Potential]

Should be zero since default behavior is unchanged.

[Other Info]

SF: #00357415