Intel 8265 driver slowness, how to debug?

eatonphil

eatonphil

I've got an intel wireless card (using the iwm8265 driver on -CURRENT). The max Mbps down I can get (according to fast.com) is around 24Mbps. However when I was running on this laptop with Linux I got at least 40Mbps on the same networks. I thought maybe it had to do with the older firmware blob that FreeBSD has for this driver so I recompiled with a newer firmware blob from Linux. That didn't change the speed. So I'm curious what in general is the cause of the slower driver on FreeBSD and how I can look into debugging/fixing slowness? Any good case-study network drivers that have been optimized on FreeBSD that I can look at for reference? Also, what difference do different versions of firmware blobs make?
 
Hi eatonphil, welcome to FreeBSD and the forums. Been a big fan of your SML advocacy over the years :beer:

You might not get many responses on this forum as discussions about -CURRENT are generally deemed off-topic. Instead, you might want to try the FreeBSD mailing lists, particularly the freebsd-wireless list. You might also want to look at the open bug report 'Add support for iwm 8265 devices' at https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=220229 for ongoing work on support for that chipset.

All the best.
 
I read the "Topics about unsupport FreeBSD versions" and was hoping this was outside of that because I'm not asking for support for this driver. Clearly this driver does not yet have the speed improvements I'm hoping for because I'm running the latest version. Instead I was hoping it wouldn't be outside the scope of this forum to ask for previous instances of driver performance enhancements so I could look into applying the techniques myself in this newer driver. However, if that is still off-topic, so be it. Thanks for the links xavi, I'll check them out. Thank you also for the /usr/src/UPDATING recommendation, SirDice.

Also, I don't believe my question about what difference versions of firmware makes has been addressed and it doesn't directly relate to the particular wireless driver I'm using.
 
eatonphil
Your topic caught my attention because I have an Intel 4-port ethernet card which uses the igb(4) driver.
And the performance is just abysmal.
There is an Intel article about FreeBSD kernel debugging and profiling. Just in case it might help.
I would really like to find out why the igb(4) driver is so slow that I replaced the card with an older card using the em(4) driver, which performs way better.
So, if you find out something, please post it. Thank you.
 
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