5 ms·

When QUIC just came out, early comments said that it makes CPU usage much higher. Is it still the same case today?

hanakuso 7y ago
Almost certainly, but I cannot confirm without benchmarks. HTTP1/2 = TCP, which has dedicated hardware to offload major parts of the protocol overhead. QUIC = UDP, but re-implements some features of TCP in software, leaving the CPU to handle things it didn't have to before.
- dragonwriter 7y ago
  Over time, especially with HTTP/3 adoption, wouldn't we expect QUIC to get hardware support like TCP, leaving this as a transitional issue?
- amluto 7y ago
  TCP hardware acceleration is generally pretty minimal. The common features are checksum offload and segmentation offload. Checksum offload should generally work for UDP, and I believe that a good UDP implementation can get much of the benefit of segmentation offloading.
marcosdumay 7y ago
As a rule, discussion of CPU usage of network protocols aren't important for 99% of the people. IO performance is the dominant metric.
- mnem 7y ago
  I'm not sure that follows. Higher CPU usage isn't undesirable because it slows things down (although it may), it prevents battery powered devices working efficiently. Plucking a figure from the air, if QUIC knocks 10% off the battery life of mobiles, that's a hard sell.
  - marcosdumay 7y ago
    Network usage of CPU is tippically well bellow rounding error on a usual system. That's different if you are talking about a static assets CDN or if you are designing networking equipment, but for usual applications, no, it won't make a difference on the battery life of your mobile, page rendering will, not network.
  - ryacko 7y ago
    Large percentage of mobile device power consumption is from radio use. Personal tests of phones in airplane mode and without airplane mode show even network keepalive consumes a fair amount of energy. I plan on purchasing the book as reviewed by this blog post: https://petewarden.com/2015/10/08/smartphone-energy-consumption/ https://petewarden.com/2015/10/08/smartphone-energy-consumpt...
    - deleted 7y ago
      [deleted]
    - krferriter 7y ago
      Sure but if HTTP/3 adds significant processor overhead compared to prior versions and the user isn't getting a noticeable benefit from this cost, they're not going to like it and it sort of seems like a pointless waste of effort.

Almost certainly, but I cannot confirm without benchmarks. HTTP1/2 = TCP, which has dedicated hardware to offload major parts of the protocol overhead. QUIC = UDP, but re-implements some features of TCP in software, leaving the CPU to handle things it didn't have to before.

dragonwriter 7y ago
Over time, especially with HTTP/3 adoption, wouldn't we expect QUIC to get hardware support like TCP, leaving this as a transitional issue?
amluto 7y ago
TCP hardware acceleration is generally pretty minimal. The common features are checksum offload and segmentation offload. Checksum offload should generally work for UDP, and I believe that a good UDP implementation can get much of the benefit of segmentation offloading.

marcosdumay 7y ago

As a rule, discussion of CPU usage of network protocols aren't important for 99% of the people. IO performance is the dominant metric.

mnem 7y ago
I'm not sure that follows. Higher CPU usage isn't undesirable because it slows things down (although it may), it prevents battery powered devices working efficiently. Plucking a figure from the air, if QUIC knocks 10% off the battery life of mobiles, that's a hard sell.
- marcosdumay 7y ago
  Network usage of CPU is tippically well bellow rounding error on a usual system. That's different if you are talking about a static assets CDN or if you are designing networking equipment, but for usual applications, no, it won't make a difference on the battery life of your mobile, page rendering will, not network.
- ryacko 7y ago
  Large percentage of mobile device power consumption is from radio use. Personal tests of phones in airplane mode and without airplane mode show even network keepalive consumes a fair amount of energy. I plan on purchasing the book as reviewed by this blog post: https://petewarden.com/2015/10/08/smartphone-energy-consumption/ https://petewarden.com/2015/10/08/smartphone-energy-consumpt...
  - deleted 7y ago
    [deleted]
  - krferriter 7y ago
    Sure but if HTTP/3 adds significant processor overhead compared to prior versions and the user isn't getting a noticeable benefit from this cost, they're not going to like it and it sort of seems like a pointless waste of effort.