4 ms·

Funny enough c7a is just what we chose recently for our CI runners precisely because of the better CPU performance. It's only better relatively to the terriblen

by paol 2y ago

Funny enough c7a is just what we chose recently for our CI runners precisely because of the better CPU performance. It's only better relatively to the terribleness of the t* types though. And it definitely costs hundreds of dollars per month. Just ran the calculator and 8 VPCUs (to keep the rough laptop analogy) comes out at $316.

re-thc 2y ago
> It's only better relatively to the terribleness of the t* types though. It's never a value add to use the t* types. That's poor misinformation or at least outdated information that people keep spreading. The advantage of c7a or Graviton 3 though is you get real cores. Most of the t* get you vCPUs, and 1/2 of it are just threads. It can be up to 2x faster in that sense. > Just ran the calculator and 8 VPCUs (to keep the rough laptop analogy) comes out at $316. Does your laptop have 8 real cores not threads that can 24/7 keep its peak speeds? Most overheat and throttle... are we comparing the same thing? ??? USD? c7a.2xlarge (8 vCPU) spot instance pricing is $0.1032 = ~$80/month (us-east-1) Even on just a 3 year compute savings plan and we're on $144.71/month. You're not required to commit to a particular instance type - just the spending, so all good? This is excluding storage. Either way there's no reason to use EC2 On-Demand without a savings plan or spot. At least commit some of it a year and it's a big saving. Otherwise don't use AWS. Side note: EPYC 5th gen has been announced and we'll likely see way more improvements on top. Pricing will definitely go down. Also: this is just a rant on AWS. Hetzner, OVH or even Oracle cloud is way cheaper, like maybe 1/2 to 1/10 of this $316... it's not a cloud issue - just AWS.
- paol 2y ago
  You're slightly off in your understanding of VCPUs. All AWS instances "get" VCPUs. A VCPU is a single thread in architectures with SMT and a single core in architectures without. So for example c7a instances which are AMD EPYCs have 1 VCPU = 1/2 core. They have is a page that lists this for every single instance type which I can't be bothered to search for right now. As for spot instances, they're a great if you can use them, but you can't hold their price as being representative. Now using savings plan prices as representative is defensible, but it won't bring the cost below the "hundreds per month" order of magnitude.
  - phonon 2y ago
    Hyperthreading is turned off on m7a/c7a/r7a. "One of the major differences between M7a instances and the previous generations of instances, such as M6a instances, is their vCPU to physical processor core mapping. Every vCPU on a M7a instance is a physical CPU core. This means there is no Simultaneous Multi-Threading (SMT). By contrast, every vCPU on prior generations such as M6a instances is a thread of a CPU core." https://aws.amazon.com/ec2/instance-types/m7a/ https://aws.amazon.com/ec2/instance-types/m7a/
    - paol 2y ago
      > Hyperthreading is turned off on m7a/c7a/r7a. You made me go check and you're right! Thanks for the correction.

by paol 2y ago

re-thc 2y ago

> It's only better relatively to the terribleness of the t* types though. It's never a value add to use the t* types. That's poor misinformation or at least outdated information that people keep spreading. The advantage of c7a or Graviton 3 though is you get real cores. Most of the t* get you vCPUs, and 1/2 of it are just threads. It can be up to 2x faster in that sense. > Just ran the calculator and 8 VPCUs (to keep the rough laptop analogy) comes out at $316. Does your laptop have 8 real cores not threads that can 24/7 keep its peak speeds? Most overheat and throttle... are we comparing the same thing? ??? USD? c7a.2xlarge (8 vCPU) spot instance pricing is $0.1032 = ~$80/month (us-east-1) Even on just a 3 year compute savings plan and we're on $144.71/month. You're not required to commit to a particular instance type - just the spending, so all good? This is excluding storage. Either way there's no reason to use EC2 On-Demand without a savings plan or spot. At least commit some of it a year and it's a big saving. Otherwise don't use AWS. Side note: EPYC 5th gen has been announced and we'll likely see way more improvements on top. Pricing will definitely go down. Also: this is just a rant on AWS. Hetzner, OVH or even Oracle cloud is way cheaper, like maybe 1/2 to 1/10 of this $316... it's not a cloud issue - just AWS.

paol 2y ago
You're slightly off in your understanding of VCPUs. All AWS instances "get" VCPUs. A VCPU is a single thread in architectures with SMT and a single core in architectures without. So for example c7a instances which are AMD EPYCs have 1 VCPU = 1/2 core. They have is a page that lists this for every single instance type which I can't be bothered to search for right now. As for spot instances, they're a great if you can use them, but you can't hold their price as being representative. Now using savings plan prices as representative is defensible, but it won't bring the cost below the "hundreds per month" order of magnitude.
- phonon 2y ago
  Hyperthreading is turned off on m7a/c7a/r7a. "One of the major differences between M7a instances and the previous generations of instances, such as M6a instances, is their vCPU to physical processor core mapping. Every vCPU on a M7a instance is a physical CPU core. This means there is no Simultaneous Multi-Threading (SMT). By contrast, every vCPU on prior generations such as M6a instances is a thread of a CPU core." https://aws.amazon.com/ec2/instance-types/m7a/ https://aws.amazon.com/ec2/instance-types/m7a/
  - paol 2y ago
    > Hyperthreading is turned off on m7a/c7a/r7a. You made me go check and you're right! Thanks for the correction.