3 ms·
If CloudFlare is using Kernel version 3.3 or higher, they should look into using fq_codel as their scheduler instead of pfifo_fast to decrease latency under loa
by virtuallynathan 13y ago
If CloudFlare is using Kernel version 3.3 or higher, they should look into using fq_codel as their scheduler instead of pfifo_fast to decrease latency under load. I suspect the 16MB buffer in the NIC isn't doing them any favors.
- croikle 13y agoTo be fair, at 10 gigabits that buffer is only 12.5 ms, but given their dedication to latency I can see it being worth investigating.
- virtuallynathan 13y agoBuffer Bloat is a real thing, it has to do with how the queuing algorithms work - I'm not the best at explaining it. I think it's mainly an issue in home routers / cable modems - but it cant hurt to do some Active Queue Management everywhere!
- eastdakota 13y agoI asked one of our kernel guys. Here's his response: "We are indeed looking at Codel. We were actually working on backporting BQL+Codel to the 2.6.x kernel but the Google guys finally got the network stack under control enough for us to deploy >3.3. The 16MB of buffers hasn't hurt us much yet, and may in the long run save us from switches that have too shallow a buffer for the high contention ratios we run on the switch." -LinuXY
- virtuallynathan 13y agoInteresting, thanks for the response!
- newman314 13y agoWhat patches from Google specifically?
- deleted 13y ago[deleted]