Re: [RFC] implement QUEUED spinlocks on powerpc

[Eric Dumazet <edumazet@google.com>]

On Mon, Feb 6, 2017 at 10:21 PM, panxinhui <xinhui@linux.vnet.ibm.com> wrote:

> hi all
>         I do some netperf tests and get some benchmark results.
> I also attach my test script and netperf-result(Excel)
>
> There are two machine. one runs netserver and the other runs netperf
> benchmark. 1000Mbps network is connected with them.
>
> #ip link infomation
> 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state
> UNKNOWN mode DEFAULT group default qlen 1000
>      link/ether ba:68:9c:14:32:02 brd ff:ff:ff:ff:ff:ff
>
> According to the results, there is not much performance gap with each other.
> And as we are only testing the throughput, the pvqspinlock shows the
> overhead of its pv stuff. but qspinlock shows a little improvement than
> spinlock. My simple summary in this testcase is
> qspinlock > spinlock > pvqspinlock.
>
> when run 200 concurrent netperf, I paste the total throughput here.
>
>         concurrent runners| total throughput | variance
> -------------------------------------------
> spinlock        | 199 | 66882.8 | 89.93
> -------------------------------------------
> qspinlock       | 199 | 66350.4 | 72.0239
> -------------------------------------------
> pvqspinlock     | 199 | 64740.5 | 85.7837
>
> You could see more data in nerperf.xlsx
>
> thanks
> xinhui


Hi xinhui

1Gbit NIC is too slow for this use case. I would try a 10Gbit NIC at least...

Alternatively, you could use loopback interface.  (netperf -H 127.0.0.1)

tc qd add dev lo root pfifo limit 10000