Messages in this thread | | | Date | Thu, 9 Apr 2015 16:46:30 +0100 | From | Stefano Stabellini <> | Subject | "tcp: refine TSO autosizing" causes performance regression on Xen |
| |
Hi all,
I found a performance regression when running netperf -t TCP_MAERTS from an external host to a Xen VM on ARM64: v3.19 and v4.0-rc4 running in the virtual machine are 30% slower than v3.18.
Through bisection I found that the perf regression is caused by the prensence of the following commit in the guest kernel:
commit 605ad7f184b60cfaacbc038aa6c55ee68dee3c89 Author: Eric Dumazet <edumazet@google.com> Date: Sun Dec 7 12:22:18 2014 -0800
tcp: refine TSO autosizing
A simple revert would fix the issue.
Does anybody have any ideas on what could be the cause of the problem? Suggestions on what to do to fix it?
Cheers,
Stefano
| |