Jedis benchmarking on local Redis server - redis

Question

I'm using JMH to test the performance of Jedis on a local Redis server (Jedis version 2.9.0, Redis version 6.2.6, CPU Quad-Core Intel Core i5). I use 200 threads to send SET command within a connection pool.
#State(Scope.Benchmark)
public class CommonClientBenchmark {
private JedisPool jedisPool;
private final String host = "127.0.0.1";
private final int port = 6379;
#Setup
public void setup() {
JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();
jedisPoolConfig.setMaxTotal(200);
jedisPoolConfig.setMaxIdle(200);
jedisPool = new JedisPool(jedisPoolConfig, host, port, 30000);
}
#TearDown
public void tearDown() {
jedisPool.close();
}
#Threads(200)
#Fork(1)
#Benchmark
#BenchmarkMode(Mode.Throughput)
#Warmup(iterations = 1, time = 30, timeUnit = TimeUnit.SECONDS)
#Measurement(iterations = 2, time = 30, timeUnit = TimeUnit.SECONDS)
public void jedisSet() {
try (Jedis jedis = jedisPool.getResource()) {
jedis.set("jedis", "jedis");
}
}
public static void main(String[] args) throws IOException, RunnerException {
CommonClientBenchmark commonClientBenchmark = new CommonClientBenchmark();
commonClientBenchmark.setup();
org.openjdk.jmh.Main.main(args);
}
}
With the code above, I obtain about 25000+ QPS. However, when I decrease the maxTotal and maxIdle parameter of the connection pool from 200 to 100, the result QPS is even much higher - it reaches about 75000. Could anyone explain the phenomenon? Thanks a lot!
EDIT: I've change the version of Jedis to 4.1.1 and run multiple benchmarking tests, the result is similar. When the size of connection pool is set to 100 (both maxTotal and maxIdle), I obtain about 25000 ~ 50000 QPS. When I increase the size (both maxTotal and maxIdle) to 200, the QPS rise to 60000 ~ 75000.
I've also use iostat 1 to monitor the usage of CPU while running the tests. And I found that when the pool size is set to 200, the %system is often much higher than when it is set to 100.
connection pool size set to 200:
disk0 cpu load average
KB/t tps MB/s us sy id 1m 5m 15m
4.09 929 3.71 7 87 6 39.58 14.44 8.06
4.00 902 3.52 6 89 5 39.58 14.44 8.06
4.50 8 0.04 5 88 6 38.33 14.60 8.15
4.39 145 0.62 6 89 6 38.33 14.60 8.15
28.00 11 0.30 6 88 5 38.33 14.60 8.15
8.00 1 0.01 5 88 6 38.33 14.60 8.15
0.00 0 0.00 5 88 7 38.33 14.60 8.15
4.00 5 0.02 5 88 7 38.94 15.12 8.37
0.00 0 0.00 5 89 6 38.94 15.12 8.37
0.00 0 0.00 5 88 7 38.94 15.12 8.37
0.00 0 0.00 5 89 6 38.94 15.12 8.37
8.68 222 1.88 5 88 7 38.94 15.12 8.37
5.60 10 0.05 5 87 8 45.20 16.81 9.01
29.65 46 1.33 11 82 7 45.20 16.81 9.01
52.57 7 0.36 8 85 7 45.20 16.81 9.01
28.00 2 0.05 5 87 8 45.20 16.81 9.01
223.33 6 1.31 6 87 7 45.20 16.81 9.01
4.19 1344 5.49 8 85 7 44.54 17.15 9.17
4.61 952 4.29 6 89 5 44.54 17.15 9.17
4.00 690 2.69 6 89 5 44.54 17.15 9.17
connection pool size set to 100:
disk0 cpu load average
KB/t tps MB/s us sy id 1m 5m 15m
4.31 13 0.05 16 59 26 6.55 7.86 7.49
750.67 3 2.20 30 53 17 6.58 7.85 7.48
9.14 225 2.01 23 54 23 6.58 7.85 7.48
37.00 8 0.29 23 56 21 6.58 7.85 7.48
32.00 6 0.19 18 55 26 6.58 7.85 7.48
145.20 10 1.41 22 56 22 6.58 7.85 7.48
0.00 0 0.00 22 56 22 6.46 7.80 7.47
4.00 2660 10.39 24 58 18 6.46 7.80 7.47
4.00 1952 7.62 19 56 25 6.46 7.80 7.47
4.00 1 0.00 19 56 24 6.46 7.80 7.47
4.00 5 0.02 18 56 27 6.46 7.80 7.47
0.00 0 0.00 15 57 28 6.10 7.71 7.44
0.00 0 0.00 18 57 25 6.10 7.71 7.44
256.00 10 2.50 18 56 25 6.10 7.71 7.44
6.29 7 0.04 20 57 23 6.10 7.71 7.44
4.00 5 0.02 20 56 24 6.10 7.71 7.44
17.71 7 0.12 20 56 24 6.01 7.66 7.42
23.00 4 0.09 20 58 23 6.01 7.66 7.42
5.00 4 0.02 23 55 22 6.01 7.66 7.42
4.00 1 0.00 20 56 24 6.01 7.66 7.42