On Thu, Apr 7, 2022 at 9:57 AM Dave Taht <dave.taht@gmail.com> wrote:
Most cloud operations websites are kept internal. gitlab's is not, which is pretty cool. In looking over this issue, today:
https://gitlab.com/gitlab-com/gl-infra/production/-/issues/6768
They are tracking tcp syn retransmits, but not drops or other congestion control related info. And also using:
sysctl net.ipv4.tcp_notsent_lowat=4294967295;
where we've been getting good results with that set as low as 32k. Anyone know anyone at gitlab?
It looks like that's their current setting, but the test they're running will be to drop it to 16K: sysctl net.ipv4.tcp_notsent_lowat=16384; It'll be interesting to see what the results of the test are, and whether 16K becomes the new "normal" for them. :) (cool to see this--I spent a certain amount of my time at my previous job doing kernel parameter tuning for large scale services, so seeing what values others are testing with is good validation. :) Matt