# FreeBSD 12 sysctl system parameters



## bagas (Feb 8, 2021)

Hello.
My system FreeBSD 12


> hw.igb.rxd="4096"
> hw.igb.txd="4096"
> hw.igb.max_interrupt_rate=32000
> hw.igb.rx_process_limit=4096



I have a network igb.
The parameters are outdated and no longer exist in the system.
Where can you read about them?


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## SirDice (Feb 8, 2021)

The old if_igb(4) driver has been merged into the if_em(4) driver.


```
root@hosaka:~ # sysctl -d hw.em
hw.em: EM driver parameters
hw.em.max_interrupt_rate: Maximum interrupts per second
hw.em.eee_setting: Enable Energy Efficient Ethernet
hw.em.rx_process_limit: Maximum number of received packets to process at a time, -1 means unlimited
hw.em.sbp: Show bad packets in promiscuous mode
hw.em.smart_pwr_down: Set to true to leave smart power down enabled on newer adapters
hw.em.rx_abs_int_delay: Default receive interrupt delay limit in usecs
hw.em.tx_abs_int_delay: Default transmit interrupt delay limit in usecs
hw.em.rx_int_delay: Default receive interrupt delay in usecs
hw.em.tx_int_delay: Default transmit interrupt delay in usecs
hw.em.disable_crc_stripping: Disable CRC Stripping
```


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## bagas (Feb 8, 2021)

But what about these parameters?
hw.igb.rxd="4096"
hw.igb.txd="4096"


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## SirDice (Feb 8, 2021)

Why do you think you need to set them in the first place? Don't tune for the sake of tuning, tune when you're running into limits.


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## bagas (Feb 8, 2021)

SirDice said:


> Why do you think you need to set them in the first place? Don't tune for the sake of tuning, tune when you're running into limits.


Server under load.





						em(4)
					






					www.freebsd.org
				



Shows what needs to be specified in loader.conf
Then why can't I see this sysctl hw.em system parameter?
hw.em.rxd
hw.em.txd


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## SirDice (Feb 8, 2021)

I don't have an answer, all I know is that these drivers have been merged into one. I suggest asking on the freebsd-net@ mailing list.


```
20170109:
        The igb(4), em(4) and lem(4) ethernet drivers are now implemented via
        IFLIB.  If you have a custom kernel configuration that excludes em(4)
        but you use igb(4), you need to re-add em(4) to your custom
        configuration.
```


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## bagas (Feb 9, 2021)

SirDice said:


> I don't have an answer, all I know is that these drivers have been merged into one. I suggest asking on the freebsd-net@ mailing list.
> 
> 
> ```
> ...


I wrote it, but it's still quiet.


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## Snurg (Feb 9, 2021)

I also have an igb card and I also am curious.
Not only rxd and txd are not recognized or shown, msix also seems affected.

The discrepancy between man page and what sysctl actually shows/accepts is obvious.
Maybe this justifies a PR?


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