HyStart testing between Princeton and NCSU
- We tested HyStart in the path between Princeton and NCSU. An estimated bandwidth for this path is 100Mbps and the RTT is 25ms. We tested CUBIC with two clock resolutions (HZ=100 and HZ=1000). The buffer auto-tuning was enabled. We applied three patches in addition to the recent patches (PATCH 0/6 TCP CUBIC and Hystart) from Stephen Hemminger.
- Tested protocols
CUBIC with SlowStart (by disabling HyStart) CUBIC with HyStart (without the patches) CUBIC with HyStart (with the patches)
Download the latest git from Linus. Apply six patches from Stephen Hemminger () Apply these three patches
Patches enabling high-resolution ACK time (if HZ < 1000) from Stephen Hemminger Problem reporting from Lucas Nussbaum Testing CUBIC from Bill Fink Discussion with Injong Rhee
- When the clock resolution is coarse (e.g., HZ < 1000), the accuracy of HyStart is affected and it may exit slow start prematurely.
- Even though Hystart found a safe exit point, it may be still slow to reach to maximum available bandwidth in long BDP paths due to initial slow growth of CUBIC.
- The above three patches solve this problem.
|Clock / Protocols||HZ = 100||HZ = 1000|
|HyStart (before fix)|