5 ms·

Except that if you saturate your uplink you will also likely make your downlink sluggish. And a user may not want to wait 20 hours for an operation to complete

by cm2187 7y ago

Except that if you saturate your uplink you will also likely make your downlink sluggish. And a user may not want to wait 20 hours for an operation to complete.

throwaway2048 7y ago
If maxing your upload slows down your download, or vice versa, its an issue with your router, anything sensible should put maximum priority on TCP acks and avoid the issue altogether.
- wtallis 7y ago
  ACK prioritization isn't always good for overall usability of an internet connection. It definitely shouldn't be used unless there's good FQ-style QoS active in both directions. Once you have that, if you're going to do anything special for ACKs, you should probably try ACK thinning before prioritizing ACKs over regular data transfers going in the same direction.
  - throwaway2048 7y ago
    what is an example of when it is bad to do this.
    - wtallis 7y ago
      If you have enough ACKs going upstream to start being a problem, you are most likely downloading a large file, and that traffic isn't particularly latency-sensitive in either direction. If you have something actually interactive that's also trying to use the same link (eg. VoIP), that traffic probably should be prioritized over a firehose of ACKs even if it will make the file download a bit slower. ACKs shouldn't be treated as any more important than the payload data they they are acknowledging. Low priority downloads should generate low-priority ACKs.
      - throwaway2048 7y ago
        ACKs are generally so small its irrelevant, unless your bandwidth is ridiculously asymmetric (less than a 23:1 ratio 64B ACK vs 1500B packet) which even really crappy cable providers don't do.
        wtallis 7y ago
        It's a very real problem for many if not most surviving DSL connections. Cable has gotten a bit better in recent years, but 10:1 is still about the best you can normally expect, and 20:1 or 25:1 is still common for some of the higher speed tiers on cable. So ACKs can realistically be expected to take up half of your upstream bandwidth on common connection types. That's far from irrelevant unless you never transmit anything other than ACKs and HTTP GETs.
        Dylan16807 7y ago
        To be fair, the example we're responding to was that asymmetric. Also for reference, most TCP stacks default to sending one ACK per two packets received.
      - cm2187 7y ago
        But ACK aren’t the only upstream traffic. Latency gets added to all your requests.
        wtallis 7y ago
        What are you trying to say? What latency is being added to what requests? Are you arguing for or against ACK prioritization?
        cm2187 7y ago
        I am neither arguing for or against, just that delayed ACK probably isn't the only reason for the connection to become sluggish. A typical page makes dozens of requests, these are packets to be uploaded, if the uplink is saturated, the latency should increase, I'd expect that to affect the time it takes to render the page.
philjohn 7y ago
Backblaze has a bandwidth limit setting if this is a concern. Yes - your first upload is going to be painful, but for the average user the following incremental backups are just a blip. And if you're a business and have lots of files to backup, well, it's leased line time.
- kenhwang 7y ago
  Took me the entire 15 day trial period for my initial backup of ~4TB. After that though, I never notice it uploading the incremental backups.
Dylan16807 7y ago
> Except that if you saturate your uplink you will also likely make your downlink sluggish. That's why I said "half". And if you make 1TB per month then it's only 10%. You could restrict it to overnight too. > And a user may not want to wait 20 hours for an operation to complete. Maybe. Tape backups are often on a daily basis anyway.
butteroverflow 7y ago
Is this normal for Windows? I assume you are talking about Windows. Maybe it depends on the quality of your network stack? I've been maxing out my uplink 24/7 for the last 10 years. My upload speed has increased from 15 KB/s to 100 Mb/s in that time, and for the life of me I could not feel or measure any difference in downlink speed or perceived performance after switching to about 1 Mb/s and up.

by cm2187 7y ago

Except that if you saturate your uplink you will also likely make your downlink sluggish. And a user may not want to wait 20 hours for an operation to complete.

throwaway2048 7y ago

If maxing your upload slows down your download, or vice versa, its an issue with your router, anything sensible should put maximum priority on TCP acks and avoid the issue altogether.

wtallis 7y ago
ACK prioritization isn't always good for overall usability of an internet connection. It definitely shouldn't be used unless there's good FQ-style QoS active in both directions. Once you have that, if you're going to do anything special for ACKs, you should probably try ACK thinning before prioritizing ACKs over regular data transfers going in the same direction.
- throwaway2048 7y ago
  what is an example of when it is bad to do this.
  - wtallis 7y ago
    If you have enough ACKs going upstream to start being a problem, you are most likely downloading a large file, and that traffic isn't particularly latency-sensitive in either direction. If you have something actually interactive that's also trying to use the same link (eg. VoIP), that traffic probably should be prioritized over a firehose of ACKs even if it will make the file download a bit slower. ACKs shouldn't be treated as any more important than the payload data they they are acknowledging. Low priority downloads should generate low-priority ACKs.
    - throwaway2048 7y ago
      ACKs are generally so small its irrelevant, unless your bandwidth is ridiculously asymmetric (less than a 23:1 ratio 64B ACK vs 1500B packet) which even really crappy cable providers don't do.
      - wtallis 7y ago
        It's a very real problem for many if not most surviving DSL connections. Cable has gotten a bit better in recent years, but 10:1 is still about the best you can normally expect, and 20:1 or 25:1 is still common for some of the higher speed tiers on cable. So ACKs can realistically be expected to take up half of your upstream bandwidth on common connection types. That's far from irrelevant unless you never transmit anything other than ACKs and HTTP GETs.
      - Dylan16807 7y ago
        To be fair, the example we're responding to was that asymmetric. Also for reference, most TCP stacks default to sending one ACK per two packets received.
    - cm2187 7y ago
      But ACK aren’t the only upstream traffic. Latency gets added to all your requests.
      - wtallis 7y ago
        What are you trying to say? What latency is being added to what requests? Are you arguing for or against ACK prioritization?
        cm2187 7y ago
        I am neither arguing for or against, just that delayed ACK probably isn't the only reason for the connection to become sluggish. A typical page makes dozens of requests, these are packets to be uploaded, if the uplink is saturated, the latency should increase, I'd expect that to affect the time it takes to render the page.

philjohn 7y ago

Backblaze has a bandwidth limit setting if this is a concern. Yes - your first upload is going to be painful, but for the average user the following incremental backups are just a blip. And if you're a business and have lots of files to backup, well, it's leased line time.

kenhwang 7y ago
Took me the entire 15 day trial period for my initial backup of ~4TB. After that though, I never notice it uploading the incremental backups.

Dylan16807 7y ago

> Except that if you saturate your uplink you will also likely make your downlink sluggish. That's why I said "half". And if you make 1TB per month then it's only 10%. You could restrict it to overnight too. > And a user may not want to wait 20 hours for an operation to complete. Maybe. Tape backups are often on a daily basis anyway.

butteroverflow 7y ago

Is this normal for Windows? I assume you are talking about Windows. Maybe it depends on the quality of your network stack? I've been maxing out my uplink 24/7 for the last 10 years. My upload speed has increased from 15 KB/s to 100 Mb/s in that time, and for the life of me I could not feel or measure any difference in downlink speed or perceived performance after switching to about 1 Mb/s and up.