I wanted to see the difference between raw io_uring compared to Cloudflare's pingora non stealing task scheduler (single threaded tokio per core) and tokio's regular task stealing scheduler.
io_uring has better throughput and P50 latency, but worse P99 and max latencies.
io_uring:
40 threads and 1000 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 1.63ms 2.40ms 57.33ms 90.01%
Req/Sec 22.13k 5.74k 99.39k 92.79%
Latency Distribution
50% 837.00us
75% 2.00ms
90% 4.03ms
99% 9.73ms
4478070 requests in 5.10s, 320.30MB read
Socket errors: connect 19, read 0, write 0, timeout 0
Requests/sec: 877837.44
Transfer/sec: 62.79MB
tokio:
40 threads and 1000 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 1.37ms 1.14ms 24.87ms 82.29%
Req/Sec 19.62k 4.69k 116.06k 93.26%
Latency Distribution
50% 1.03ms
75% 1.70ms
90% 2.81ms
99% 5.56ms
3952985 requests in 5.09s, 282.74MB read
Socket errors: connect 19, read 0, write 0, timeout 0
Requests/sec: 776239.06
Transfer/sec: 55.52MB
pigora's single threaded tokio per core:
40 threads and 1000 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 1.34ms 499.93us 9.27ms 76.29%
Req/Sec 18.15k 5.09k 207.43k 95.67%
Latency Distribution
50% 1.28ms
75% 1.59ms
90% 1.92ms
99% 2.89ms
3672542 requests in 5.10s, 262.68MB read
Socket errors: connect 19, read 0, write 0, timeout 0
Requests/sec: 720086.93
Transfer/sec: 51.50MB
These were run on my machine (System76 lemp11).
For regular run:
gcc main.c -O3 -luring -o main
./main
# On another terminal
wrk -t40 -c1000 -d10 http://127.0.0.1:3003 --latencyFor flamegraph:
gcc main.c -O3 -luring -g -fno-omit-frame-pointer -o main
perf record -g ./main
# On another terminal
wrk -t40 -c1000 -d10 http://127.0.0.1:3003 --latency
# ^C perf when done measuring and then:
./gen_flamegraph.sh
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