5 ms·

> And I was fairly certain I hadn't enabled the "FAIL_MAIL_OVER_500_MILES" option. If this actually was a config option, I would bet anything the default would

> And I was fairly certain I hadn't enabled the "FAIL_MAIL_OVER_500_MILES" option. If this actually was a config option, I would bet anything the default would inexplicably be set to "true".

komali2 9y ago
It's like this weird setting in Ubuntu's network driver config file, "11n_disable." I won't pretend to know much about it but every time I install Ubuntu on a machine, wifi internet speeds are slow until I set the above to "8". To me it seems like literally a "go faster" switch.
- rincebrain 9y ago
  Only 8, and not 1? Because, at least on my system, looking at iwlwifi... parm: 11n_disable:disable 11n functionality, bitmap: 1: full, 2: disable agg TX, 4: disable agg RX, 8 enable agg TX (uint) So 8 is only aggregated TX, while 1 would be aggregated TX and RX. (It does, however, also inexplicably default to 0 on my system.)
  - komali2 9y ago
    Oh neat, lemme try that out then.
    - rincebrain 9y ago
      I'd be curious to learn what it does for you, because my intuitive interpretation would say that 1 would be "disable all", but that doesn't explain why "enable agg TX" would be an improvement unless agg RX is worse than the baseline...which is probably a bug. e: Oh, apparently this is a pathological re-use of an existing module flag to force something on that they disabled due to instability in some cases, see also: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=205e2210daa975d92ace485a65a31ccc4077fe1a https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin... So I'm sorry, but my assumption about =1 is not valid, as I assumed that all of the bits (1,2,4,8) were mutating the same thing, not "one bit does something VERY DIFFERENT".
- kroo 9y ago
  Ok, this got me curious... 11n_disable=8? A quick google turns up lots of people agreeing with you, suggesting the intel wireless driver seems to have trouble on 802.11n. Fine. But 8? modinfo iwlwifi shows us that 11n_disable is actually a bitmask: parm: 11n_disable:disable 11n functionality, bitmap: 1: full, 2: disable agg TX, 4: disable agg RX, 8 enable agg TX (uint) Ahah, your story is starting to make more sense! Setting the value above 8 would set the 'enable agg TX' bit in this bitmask. Side note: 11n_disable=8 as a way to enable an advanced wifi settings is not the most user-friendly option in the world. It looks like this was added as a patch to fix a compatibility issue with certain NICs[1]. Be careful setting it higher than 8 -- as that would set other flags in the bitmask, potentially turning off 802.11n entirely! I've not heard of AMPDU before -- but it seems to be an 802.11n-specific protocol extension that allows you to send multiple MPDU blocks (i.e. frames) to the router at a time, rather than one at a time. This seems to trade off latency for error correction between a client and the router [2][3]. So by setting this flag, you're able to transmit multiple frames at a time, rather than retrying each frame individually until it goes through on a busy channel. This really does seem to make a difference, one report online suggests tx throughput goes from 20Mbit/s to 80Mbit/s when agg TX is enabled[4]. Apparently this was introduced in 2014 in order to patch a firmware issue on certain intel NICs. There's a whole conversation on the linux-wireless list about it[5], which seems to conclude that they couldn't reproduce the issue[6]: > I have seen reports from many users and many devices - and unfortunately I have never been able to reproduce - so I can't know if it affects all the devices. All I can see is that I saw reports on very old devices (5150) and with more recent devices (2230). [1]: https://github.com/torvalds/linux/commit/205e2210daa975d92ace485a65a31ccc4077fe1a https://github.com/torvalds/linux/commit/205e2210daa975d92ac... [2]: https://routerguide.net/optimize-ampdu-aggregation-on-or-off-a-mpdu/ https://routerguide.net/optimize-ampdu-aggregation-on-or-off... [3]: http://eprints.eemcs.utwente.nl/21008/01/eunice.pdf http://eprints.eemcs.utwente.nl/21008/01/eunice.pdf [4]: https://ubuntuforums.org/printthread.php?t=2205924&pp=75 https://ubuntuforums.org/printthread.php?t=2205924&pp=75 [5]: https://www.spinics.net/lists/linux-wireless/msg118549.html https://www.spinics.net/lists/linux-wireless/msg118549.html [6]: https://www.spinics.net/lists/linux-wireless/msg118554.html https://www.spinics.net/lists/linux-wireless/msg118554.html
  - komali2 9y ago
- Faaak 9y ago
  I can't find the "11n_disable." option. Are you talking about the "11n_disable" ? The importance of full stops outside the quotes ;-)
  - eat_veggies 9y ago
    When you end a sentence with a quotation you put the punctuation within the quote.
    - Piskvorrr 9y ago
      Not in English you don't.
      - sa46 9y ago
        American style (Chicago, APA, and MLA) specifies that a period goes inside the quotations. British style, on the other hand, specifies that a period goes outside the quotations. http://blog.apastyle.org/apastyle/2011/08/punctuating-around-quotation-marks.html http://blog.apastyle.org/apastyle/2011/08/punctuating-around...
        DamonHD 9y ago
        As as Brit I was taught to put it inside, but I treat that rule as a strong hint which may be overridden if other complication is happening there...
      - bradknowles 9y ago
        As I recall, according to "Strunk and White", and the "Chicago Manual of Style", all punctuation is supposed to be included inside the quote characters. I happen to disagree with them, but they have been considered authorities on the proper way to write in the English language for many decades.

> And I was fairly certain I hadn't enabled the "FAIL_MAIL_OVER_500_MILES" option. If this actually was a config option, I would bet anything the default would inexplicably be set to "true".

komali2 9y ago

It's like this weird setting in Ubuntu's network driver config file, "11n_disable." I won't pretend to know much about it but every time I install Ubuntu on a machine, wifi internet speeds are slow until I set the above to "8". To me it seems like literally a "go faster" switch.

rincebrain 9y ago
Only 8, and not 1? Because, at least on my system, looking at iwlwifi... parm: 11n_disable:disable 11n functionality, bitmap: 1: full, 2: disable agg TX, 4: disable agg RX, 8 enable agg TX (uint) So 8 is only aggregated TX, while 1 would be aggregated TX and RX. (It does, however, also inexplicably default to 0 on my system.)
- komali2 9y ago
  Oh neat, lemme try that out then.
  - rincebrain 9y ago
    I'd be curious to learn what it does for you, because my intuitive interpretation would say that 1 would be "disable all", but that doesn't explain why "enable agg TX" would be an improvement unless agg RX is worse than the baseline...which is probably a bug. e: Oh, apparently this is a pathological re-use of an existing module flag to force something on that they disabled due to instability in some cases, see also: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=205e2210daa975d92ace485a65a31ccc4077fe1a https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin... So I'm sorry, but my assumption about =1 is not valid, as I assumed that all of the bits (1,2,4,8) were mutating the same thing, not "one bit does something VERY DIFFERENT".
kroo 9y ago
Ok, this got me curious... 11n_disable=8? A quick google turns up lots of people agreeing with you, suggesting the intel wireless driver seems to have trouble on 802.11n. Fine. But 8? modinfo iwlwifi shows us that 11n_disable is actually a bitmask: parm: 11n_disable:disable 11n functionality, bitmap: 1: full, 2: disable agg TX, 4: disable agg RX, 8 enable agg TX (uint) Ahah, your story is starting to make more sense! Setting the value above 8 would set the 'enable agg TX' bit in this bitmask. Side note: 11n_disable=8 as a way to enable an advanced wifi settings is not the most user-friendly option in the world. It looks like this was added as a patch to fix a compatibility issue with certain NICs[1]. Be careful setting it higher than 8 -- as that would set other flags in the bitmask, potentially turning off 802.11n entirely! I've not heard of AMPDU before -- but it seems to be an 802.11n-specific protocol extension that allows you to send multiple MPDU blocks (i.e. frames) to the router at a time, rather than one at a time. This seems to trade off latency for error correction between a client and the router [2][3]. So by setting this flag, you're able to transmit multiple frames at a time, rather than retrying each frame individually until it goes through on a busy channel. This really does seem to make a difference, one report online suggests tx throughput goes from 20Mbit/s to 80Mbit/s when agg TX is enabled[4]. Apparently this was introduced in 2014 in order to patch a firmware issue on certain intel NICs. There's a whole conversation on the linux-wireless list about it[5], which seems to conclude that they couldn't reproduce the issue[6]: > I have seen reports from many users and many devices - and unfortunately I have never been able to reproduce - so I can't know if it affects all the devices. All I can see is that I saw reports on very old devices (5150) and with more recent devices (2230). [1]: https://github.com/torvalds/linux/commit/205e2210daa975d92ace485a65a31ccc4077fe1a https://github.com/torvalds/linux/commit/205e2210daa975d92ac... [2]: https://routerguide.net/optimize-ampdu-aggregation-on-or-off-a-mpdu/ https://routerguide.net/optimize-ampdu-aggregation-on-or-off... [3]: http://eprints.eemcs.utwente.nl/21008/01/eunice.pdf http://eprints.eemcs.utwente.nl/21008/01/eunice.pdf [4]: https://ubuntuforums.org/printthread.php?t=2205924&pp=75 https://ubuntuforums.org/printthread.php?t=2205924&pp=75 [5]: https://www.spinics.net/lists/linux-wireless/msg118549.html https://www.spinics.net/lists/linux-wireless/msg118549.html [6]: https://www.spinics.net/lists/linux-wireless/msg118554.html https://www.spinics.net/lists/linux-wireless/msg118554.html
- komali2 9y ago
Faaak 9y ago
I can't find the "11n_disable." option. Are you talking about the "11n_disable" ? The importance of full stops outside the quotes ;-)
- eat_veggies 9y ago
  When you end a sentence with a quotation you put the punctuation within the quote.
  - Piskvorrr 9y ago
    Not in English you don't.
    - sa46 9y ago
      American style (Chicago, APA, and MLA) specifies that a period goes inside the quotations. British style, on the other hand, specifies that a period goes outside the quotations. http://blog.apastyle.org/apastyle/2011/08/punctuating-around-quotation-marks.html http://blog.apastyle.org/apastyle/2011/08/punctuating-around...
      - DamonHD 9y ago
        As as Brit I was taught to put it inside, but I treat that rule as a strong hint which may be overridden if other complication is happening there...
    - bradknowles 9y ago
      As I recall, according to "Strunk and White", and the "Chicago Manual of Style", all punctuation is supposed to be included inside the quote characters. I happen to disagree with them, but they have been considered authorities on the proper way to write in the English language for many decades.