[RFC] implement QUEUED spinlocks on powerpc

[panxinhui]

在 2017/2/7 下午2:46, Eric Dumazet 写道:
> On Mon, Feb 6, 2017 at 10:21 PM, panxinhui <xinhui at 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)
>>
HI, all
I use loopback interface to run netperf tests,
#tc qd add dev lo root pfifo limit 10000
#ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc pfifo state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

and put the result in netperf.xlsx(excel)

It is a 32 vcpus P8 machine, with 32Gib memory.

This time spinlock is the best one, qspinlock > pvqspinlock. So sad.

thanks
xinhui
>> 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
> 
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