HEADS-UP: IFLIB implementations of sys/dev/e1000 em, lem, igb pending

[Sean Bruno]

On 01/24/17 08:27, Olivier Cochard-Labbé wrote:
> On Tue, Jan 24, 2017 at 3:17 PM, Sean Bruno <sbruno at freebsd.org
> <mailto:sbruno at freebsd.org>> wrote:
> 
> 
> 
>     Did you increase the number of rx/tx rings to 8 and the number of
>     descriptors to 4k in your tests or just the defaults?
> 
> 
> Tuning are same as described in my previous email (rxd|txd=2048, rx|tx
> process_limit=-1, max_interrupt_rate=16000).
> [root at apu2]~# sysctl hw.igb.
> hw.igb.tx_process_limit: -1
> hw.igb.rx_process_limit: -1
> hw.igb.num_queues: 0
> hw.igb.header_split: 0
> hw.igb.max_interrupt_rate: 16000
> hw.igb.enable_msix: 1
> hw.igb.enable_aim: 1
> hw.igb.txd: 2048
> hw.igb.rxd: 2048
> 
> 

Oh, I think you missed my note on these.  In order to adjust txd/rxd you
need to tweak the iflib version of these numbers.  nrxds/ntxds should be
adjust upwards to your value of 2048.  nrxqs/ntxqs should be adjust
upwards to 8, I think, so you can test equivalent settings to the legacy
driver.

Specifically, you may want to adjust these:

dev.em.0.iflib.override_nrxds: 0
dev.em.0.iflib.override_ntxds: 0

dev.em.0.iflib.override_nrxqs: 0
dev.em.0.iflib.override_ntxqs: 0

sean

> But I've did a new benchs with default setting, and the performance drop
> is now about -25% :
> 
> x head r311848 packets-per-second (default settings)
> + head r311849 packets-per-second (default settings)
> +--------------------------------------------------------------------------+
> |+                                                                         |
> |+                                                                       x |
> |+                                                                       xx|
> |++                                                                      xx|
> |                                                                        A||
> |A|                                                                        |
> +--------------------------------------------------------------------------+
>     N           Min           Max        Median           Avg        Stddev
> x   5        618711        621135      619930.5      619840.8     951.83787
> +   5        467389        468740        467778      467864.8     550.40322
> Difference at 95.0% confidence
>         -151976 +/- 1133.9
>         -24.5186% +/- 0.150581%
>         (Student's t, pooled s = 777.476)
> 

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