3 ms·

I'm not 100% convinced by the 5115 vs 4116, but that will depend on the workload. The case is clear for the 6126, but "For just a few hundred more dollars" is a

by temac 7y ago

I'm not 100% convinced by the 5115 vs 4116, but that will depend on the workload. The case is clear for the 6126, but "For just a few hundred more dollars" is a bit dishonest; you are talking about $1000 (for the 4116) vs $1770 (for the 6126). Now IF you are going to do AVX2/AVX512 like crazy and have the money, sure, go for it. But it is not a case of "oh but for just a little bit more, I've got way much better". And that's even considering other costs. Cause you can use that reasoning for all components, so in the end does ×1.7 really not matter? Not so sure... Hey even $770 vs. amortization through increased performance can be difficult to reach sometimes - that's also very workload / business model dependent. Also if you actually needs tons of processors, availability might be an issue. Now in the end, I'm not familiar enough with Cloudfare needs and I know that pretty much anybody can make mistakes, so it is possible that they should have gone with something like the 6126 instead of 4116. But then the 8124? hm, less probable.

Twirrim 7y ago
4116 release price was $1002 5115 release price was $1221 For "just a few hundred more dollars", you got two less cores, but notably better AVX-512 scaling. 5118 release price was $1273, https://en.wikichip.org/wiki/intel/xeon_gold/5118 https://en.wikichip.org/wiki/intel/xeon_gold/5118. That keeps you in the 12 core range, still only a hundred dollars more than the option they went with. Also bare in mind those are RRPs, which Cloudflare likely isn't paying, especially at the scales they're operating at. The crux of the point was that they were apparently surprised when a chip that wasn't designed for the kind of workload they decided to use it for, didn't perform well. It's like buying small car and then being surprised that it doesn't have the same hauling power as a truck. Frustratingly, everyone has taken it as gospel that it means AVX-512 is entirely crap and just going to hurt you. It definitely has made optimising a bit more complicated. You could certainly argue that you might need to have the runtime profiling the code to figure out if using AVX-512 is harmful or not.

by temac 7y ago

Twirrim 7y ago

4116 release price was $1002 5115 release price was $1221 For "just a few hundred more dollars", you got two less cores, but notably better AVX-512 scaling. 5118 release price was $1273, https://en.wikichip.org/wiki/intel/xeon_gold/5118 https://en.wikichip.org/wiki/intel/xeon_gold/5118. That keeps you in the 12 core range, still only a hundred dollars more than the option they went with. Also bare in mind those are RRPs, which Cloudflare likely isn't paying, especially at the scales they're operating at. The crux of the point was that they were apparently surprised when a chip that wasn't designed for the kind of workload they decided to use it for, didn't perform well. It's like buying small car and then being surprised that it doesn't have the same hauling power as a truck. Frustratingly, everyone has taken it as gospel that it means AVX-512 is entirely crap and just going to hurt you. It definitely has made optimising a bit more complicated. You could certainly argue that you might need to have the runtime profiling the code to figure out if using AVX-512 is harmful or not.