Netty on OSv and Local loopback latency

Jestan Nirojan

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Sep 24, 2013, 2:55:58 PM9/24/13

to osv...@googlegroups.com

Hi all,

I have got a Netty application working on OSv https://github.com/jestan/netty-osv-perf.

Starting the application is very fast :) and it completed the task faster than my host PC (sending 8 byte messages from client to server in ping pong fashion 100000 times)

and its great, keep up the good work guys.

but I have got following histogram results for the latency, i was hoping that it would be close to few nano seconds, any idea why the latency is like this?

[/tmp]% cat netty-perf6167611028991339554.tmp

************************************************

********** Running NioTcpLatencyTest **********

Histogram {

min=430000, max=12099000, mean=3315416.45, 99%=11500000, 99.99%=12100000

intervals = [

50000=0,

100000=0,

150000=0,

200000=0,

250000=0,

300000=0,

350000=0,

400000=0,

450000=35,

500000=35,

550000=105,

600000=152,

650000=71,

700000=105,

750000=199,

800000=216,

850000=543,

900000=342,

950000=239,

1000000=686,

1050000=685,

1100000=393,

1150000=0,

1200000=319,

1250000=183,

1300000=641,

1350000=283,

1400000=1193,

1450000=1109,

1500000=1333,

1550000=881,

1600000=947,

1650000=1429,

1700000=1834,

1750000=2114,

1800000=2607,

1850000=1874,

1900000=1340,

1950000=1961,

2000000=1774,

2050000=916,

2100000=1016,

2150000=1976,

2200000=1243,

2250000=1150,

2300000=686,

2350000=884,

2400000=171,

2450000=265,

2500000=139,

2550000=290,

2600000=177,

2650000=110,

2700000=658,

2750000=580,

2800000=108,

2850000=236,

2900000=693,

2950000=870,

3000000=737,

3050000=1415,

3100000=1494,

3150000=1535,

3200000=1277,

3250000=1073,

3300000=1179,

3350000=1617,

3400000=2014,

3450000=1734,

3500000=1702,

3550000=1557,

3600000=1628,

3650000=1392,

3700000=1039,

3750000=691,

3800000=687,

3850000=699,

3900000=563,

3950000=365,

4000000=267,

4050000=149,

4100000=86,

4150000=86,

4200000=74,

4250000=70,

4300000=104,

4350000=353,

4400000=527,

4450000=517,

4500000=66,

4550000=66,

4600000=343,

4650000=225,

4700000=25,

4750000=24,

4800000=25,

4850000=25,

4900000=28,

4950000=27,

5000000=19,

5050000=186,

5100000=306,

5150000=113,

5200000=0,

5250000=0,

5300000=12,

5350000=96,

5400000=239,

5450000=440,

5500000=30,

5550000=27,

5600000=37,

5650000=200,

5700000=91,

5750000=62,

5800000=38,

5850000=19,

5900000=19,

5950000=228,

6000000=348,

6050000=332,

6100000=123,

6150000=17,

6200000=17,

6250000=290,

6300000=331,

6350000=28,

6400000=17,

6450000=16,

6500000=29,

6550000=39,

6600000=47,

6650000=66,

6700000=64,

6750000=81,

6800000=82,

6850000=84,

6900000=64,

6950000=59,

7000000=59,

7050000=56,

7100000=61,

7150000=62,

7200000=54,

7250000=40,

7300000=33,

7350000=31,

7400000=38,

7450000=58,

7500000=99,

7550000=72,

7600000=64,

7650000=228,

7700000=170,

7750000=69,

7800000=437,

7850000=535,

7900000=140,

7950000=269,

8000000=113,

8050000=68,

8100000=75,

8150000=52,

8200000=55,

8250000=26,

8300000=51,

8350000=18,

8400000=32,

8450000=50,

8500000=51,

8550000=26,

8600000=18,

8650000=17,

8700000=17,

8750000=363,

8800000=26,

8850000=31,

8900000=29,

8950000=22,

9000000=18,

9050000=14,

9100000=1,

9150000=0,

9200000=0,

9250000=0,

9300000=0,

9350000=0,

9400000=0,

9450000=0,

9500000=0,

9550000=0,

9600000=0,

9650000=0,

9700000=0,

9750000=0,

9800000=0,

9850000=0,

9900000=0,

9950000=0,

10000000=0,

10050000=8,

10100000=13,

10150000=13,

10200000=12,

10250000=14,

10300000=47,

10350000=13,

10400000=47,

10450000=13,

10500000=13,

10550000=13,

10600000=48,

10650000=13,

10700000=48,

10750000=16,

10800000=33,

10850000=29,

10900000=68,

10950000=34,

11000000=29,

11050000=14,

11100000=26,

11150000=220,

11200000=219,

11250000=245,

11300000=95,

11350000=272,

11400000=264,

11450000=181,

11500000=138,

11550000=10,

11600000=14,

11650000=109,

11700000=148,

11750000=132,

11800000=170,

11850000=93,

11900000=0,

11950000=0,

12000000=0,

12050000=0,

12100000=35,

12150000=0,

12200000=0,

12250000=0,

12300000=0,

12350000=0,

12400000=0,

12450000=0,

12500000=0,

12550000=0,

12600000=0,

12650000=0,

12700000=0,

12750000=0]

}

************************************************

-Jestan

Pekka Enberg

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Sep 26, 2013, 3:49:24 AM9/26/13

to Jestan Nirojan, Osv Dev

Hi Jestan,

On Tue, Sep 24, 2013 at 9:55 PM, Jestan Nirojan <jestan...@gmail.com> wrote:
> I have got a Netty application working on OSv
> https://github.com/jestan/netty-osv-perf.
>
> Starting the application is very fast :) and it completed the task faster
> than my host PC (sending 8 byte messages from client to server in ping pong
> fashion 100000 times)
> and its great, keep up the good work guys.
>
> but I have got following histogram results for the latency, i was hoping
> that it would be close to few nano seconds, any idea why the latency is like
> this?

What exactly are you trying to measure here? OSv loopback latency? The
test case runs such a short amount of time, you're also measuring
Hotspot JIT compilation...

Microbenchmarks are very hard to get right on the JVM. I strongly
recommend porting the test to JMH before continuing with the
experiment:

http://openjdk.java.net/projects/code-tools/jmh/

Pekka

Jestan Nirojan

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Sep 26, 2013, 9:51:15 AM9/26/13

to osv...@googlegroups.com, Jestan Nirojan

Hi Pekka,

I will port the test to JMH and see. thank you for suggesting JMH.

I was not trying to measure the OSv loopback latency. I was trying to compare with the numbers I got with host OS since OSv has low overhead.

The application I wrote has some resource leak and there are thousands of exceptions thrown (some resource leak detection exception from Netty), so I have to fix it before starting JMH port. (The resource leak exception has nothing to do with OSv)