はじめに
仮想環境ではパフォーマンスが低下する傾向があります。
これはVMwareやKVMでも発生しており、dockerでもこの現象が発生すると言われていますが、実際に性能が低下するのか調べてみました。
調査方法はUnixBenchです。CPU/Mem/Storageの試験を行います。
環境
Cloud: ConoHa 512GB (最安モデル)
OS: Rocky Linux 8.6
実行
docker無し(ネイティブのLinux):
yum install -y perl gcc git
mkdir unixbench
cd unixbench/
git clone https://github.com/kdlucas/byte-unixbench.git .
cd UnixBench/
./Rundocker有り：
yum install -y yum-utils
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
yum install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
systemctl start docker
docker run -it tukiyo3/centos7-unixbench結果・まとめ
早速ですが結果です。実行結果は別にまとめています。
| 環境 | 総合スコア | 浮動小数点 | ファイルコピー | Shell |
| docker無し(native) | 1568.7 | 11194.3 MWIPS | 2466821.1 KBps | 6103.0 lpm |
| docker有り | 1372.8 | 8911.4 MWIPS | 1852100.6 KBps | 6056.8 lpm |
| 低下率 | 12.5% | 20.4% | 24.9% | 0.8% |
見ての通り、dockerを使用すると総合スコアで約12.5%のパフォーマンス低下があるようです。
しかし、計測項目によって大きく異なります。浮動小数点計算(CPU性能)では20.4%の低下となっており、ファイルコピー(ストレージ性能)に至っては24.9%とかなり大きなパフォーマンス低下が確認できます。
一方で、shellスクリプトの実行などでは0.8%の低下となっており、ほぼパフォーマン低下はありません。
とはいえ、CPUやストレージ周りなど頻繁に使用する機能が20%を超えるパフォーマンス低下があるのはよろしくありません。
動作環境として、dockerにしなければならない必要性が無い場合は必ずしも使う必要はないと思います。
参考：UnixBenchデータ
docker無し(native)：
========================================================================
BYTE UNIX Benchmarks (Version 5.1.3)
System: 160-251-15-80: GNU/Linux
OS: GNU/Linux -- 4.18.0-372.26.1.el8_6.x86_64 -- #1 SMP Tue Sep 13 18:09:48 UTC 2022
Machine: x86_64 (x86_64)
Language: en_US.utf8 (charmap="UTF-8", collate="UTF-8")
CPU 0: Intel(R) Xeon(R) CPU E5-2640 v4 @ 2.40GHz (4794.4 bogomips)
x86-64, MMX, Physical Address Ext, SYSENTER/SYSEXIT, SYSCALL/SYSRET
CPU 1: Intel(R) Xeon(R) CPU E5-2640 v4 @ 2.40GHz (4794.4 bogomips)
x86-64, MMX, Physical Address Ext, SYSENTER/SYSEXIT, SYSCALL/SYSRET
05:00:56 up 317 days, 11:23, 1 user, load average: 0.00, 0.54, 1.96; runlevel 2022-10-30
------------------------------------------------------------------------
Benchmark Run: Wed Sep 13 2023 05:00:56 - 05:28:51
2 CPUs in system; running 1 parallel copy of tests
Dhrystone 2 using register variables 31240199.1 lps (10.0 s, 7 samples)
Double-Precision Whetstone 5566.0 MWIPS (9.1 s, 7 samples)
Execl Throughput 2394.5 lps (30.0 s, 2 samples)
File Copy 1024 bufsize 2000 maxblocks 553399.8 KBps (30.0 s, 2 samples)
File Copy 256 bufsize 500 maxblocks 148977.3 KBps (30.0 s, 2 samples)
File Copy 4096 bufsize 8000 maxblocks 1245792.3 KBps (30.0 s, 2 samples)
Pipe Throughput 827851.3 lps (10.0 s, 7 samples)
Pipe-based Context Switching 90528.9 lps (10.0 s, 7 samples)
Process Creation 6200.1 lps (30.0 s, 2 samples)
Shell Scripts (1 concurrent) 4455.0 lpm (60.0 s, 2 samples)
Shell Scripts (8 concurrent) 856.2 lpm (60.1 s, 2 samples)
System Call Overhead 588730.3 lps (10.0 s, 7 samples)
System Benchmarks Index Values BASELINE RESULT INDEX
Dhrystone 2 using register variables 116700.0 31240199.1 2677.0
Double-Precision Whetstone 55.0 5566.0 1012.0
Execl Throughput 43.0 2394.5 556.9
File Copy 1024 bufsize 2000 maxblocks 3960.0 553399.8 1397.5
File Copy 256 bufsize 500 maxblocks 1655.0 148977.3 900.2
File Copy 4096 bufsize 8000 maxblocks 5800.0 1245792.3 2147.9
Pipe Throughput 12440.0 827851.3 665.5
Pipe-based Context Switching 4000.0 90528.9 226.3
Process Creation 126.0 6200.1 492.1
Shell Scripts (1 concurrent) 42.4 4455.0 1050.7
Shell Scripts (8 concurrent) 6.0 856.2 1427.0
System Call Overhead 15000.0 588730.3 392.5
========
System Benchmarks Index Score 865.9
------------------------------------------------------------------------
Benchmark Run: Wed Sep 13 2023 05:28:51 - 05:56:47
2 CPUs in system; running 2 parallel copies of tests
Dhrystone 2 using register variables 61493628.5 lps (10.0 s, 7 samples)
Double-Precision Whetstone 11194.3 MWIPS (9.1 s, 7 samples)
Execl Throughput 3516.1 lps (29.7 s, 2 samples)
File Copy 1024 bufsize 2000 maxblocks 977039.7 KBps (30.0 s, 2 samples)
File Copy 256 bufsize 500 maxblocks 264470.4 KBps (30.0 s, 2 samples)
File Copy 4096 bufsize 8000 maxblocks 2466821.1 KBps (30.0 s, 2 samples)
Pipe Throughput 1641487.2 lps (10.0 s, 7 samples)
Pipe-based Context Switching 367545.8 lps (10.0 s, 7 samples)
Process Creation 9572.6 lps (30.0 s, 2 samples)
Shell Scripts (1 concurrent) 6103.0 lpm (60.0 s, 2 samples)
Shell Scripts (8 concurrent) 927.9 lpm (60.1 s, 2 samples)
System Call Overhead 1104965.1 lps (10.0 s, 7 samples)
System Benchmarks Index Values BASELINE RESULT INDEX
Dhrystone 2 using register variables 116700.0 61493628.5 5269.4
Double-Precision Whetstone 55.0 11194.3 2035.3
Execl Throughput 43.0 3516.1 817.7
File Copy 1024 bufsize 2000 maxblocks 3960.0 977039.7 2467.3
File Copy 256 bufsize 500 maxblocks 1655.0 264470.4 1598.0
File Copy 4096 bufsize 8000 maxblocks 5800.0 2466821.1 4253.1
Pipe Throughput 12440.0 1641487.2 1319.5
Pipe-based Context Switching 4000.0 367545.8 918.9
Process Creation 126.0 9572.6 759.7
Shell Scripts (1 concurrent) 42.4 6103.0 1439.4
Shell Scripts (8 concurrent) 6.0 927.9 1546.5
System Call Overhead 15000.0 1104965.1 736.6
========
System Benchmarks Index Score 1568.7docker:
========================================================================
BYTE UNIX Benchmarks (Version 5.1.3)
System: : GNU/Linux
OS: GNU/Linux -- 4.18.0-372.26.1.el8_6.x86_64 -- #1 SMP Tue Sep 13 18:09:48 UTC 2022
Machine: x86_64 (x86_64)
Language: en_US.utf8 (charmap="UTF-8", collate="UTF-8")
CPU 0: Intel(R) Xeon(R) CPU E5-2640 v4 @ 2.40GHz (4794.4 bogomips)
x86-64, MMX, Physical Address Ext, SYSENTER/SYSEXIT, SYSCALL/SYSRET
CPU 1: Intel(R) Xeon(R) CPU E5-2640 v4 @ 2.40GHz (4794.4 bogomips)
x86-64, MMX, Physical Address Ext, SYSENTER/SYSEXIT, SYSCALL/SYSRET
19:51:09 up 317 days, 10:13, 0 users, load average: 0.84, 0.37, 0.14; runlevel
------------------------------------------------------------------------
Benchmark Run: Tue Sep 12 2023 19:51:09 - 20:19:12
2 CPUs in system; running 1 parallel copy of tests
Dhrystone 2 using register variables 28929058.3 lps (10.0 s, 7 samples)
Double-Precision Whetstone 4451.5 MWIPS (9.8 s, 7 samples)
Execl Throughput 2270.9 lps (30.0 s, 2 samples)
File Copy 1024 bufsize 2000 maxblocks 406495.7 KBps (30.0 s, 2 samples)
File Copy 256 bufsize 500 maxblocks 111727.8 KBps (30.0 s, 2 samples)
File Copy 4096 bufsize 8000 maxblocks 959760.1 KBps (30.0 s, 2 samples)
Pipe Throughput 739111.4 lps (10.0 s, 7 samples)
Pipe-based Context Switching 80833.2 lps (10.0 s, 7 samples)
Process Creation 5819.1 lps (30.0 s, 2 samples)
Shell Scripts (1 concurrent) 4382.8 lpm (60.0 s, 2 samples)
Shell Scripts (8 concurrent) 864.3 lpm (60.0 s, 2 samples)
System Call Overhead 585703.5 lps (10.0 s, 7 samples)
System Benchmarks Index Values BASELINE RESULT INDEX
Dhrystone 2 using register variables 116700.0 28929058.3 2478.9
Double-Precision Whetstone 55.0 4451.5 809.4
Execl Throughput 43.0 2270.9 528.1
File Copy 1024 bufsize 2000 maxblocks 3960.0 406495.7 1026.5
File Copy 256 bufsize 500 maxblocks 1655.0 111727.8 675.1
File Copy 4096 bufsize 8000 maxblocks 5800.0 959760.1 1654.8
Pipe Throughput 12440.0 739111.4 594.1
Pipe-based Context Switching 4000.0 80833.2 202.1
Process Creation 126.0 5819.1 461.8
Shell Scripts (1 concurrent) 42.4 4382.8 1033.7
Shell Scripts (8 concurrent) 6.0 864.3 1440.5
System Call Overhead 15000.0 585703.5 390.5
========
System Benchmarks Index Score 763.4
------------------------------------------------------------------------
Benchmark Run: Tue Sep 12 2023 20:19:12 - 20:47:15
2 CPUs in system; running 2 parallel copies of tests
Dhrystone 2 using register variables 57873095.9 lps (10.0 s, 7 samples)
Double-Precision Whetstone 8911.4 MWIPS (9.8 s, 7 samples)
Execl Throughput 3441.8 lps (30.0 s, 2 samples)
File Copy 1024 bufsize 2000 maxblocks 736707.9 KBps (30.0 s, 2 samples)
File Copy 256 bufsize 500 maxblocks 192650.5 KBps (30.0 s, 2 samples)
File Copy 4096 bufsize 8000 maxblocks 1852100.6 KBps (30.0 s, 2 samples)
Pipe Throughput 1478410.2 lps (10.0 s, 7 samples)
Pipe-based Context Switching 292767.1 lps (10.0 s, 7 samples)
Process Creation 8627.3 lps (30.0 s, 2 samples)
Shell Scripts (1 concurrent) 6056.8 lpm (60.0 s, 2 samples)
Shell Scripts (8 concurrent) 961.9 lpm (60.0 s, 2 samples)
System Call Overhead 1108283.9 lps (10.0 s, 7 samples)
System Benchmarks Index Values BASELINE RESULT INDEX
Dhrystone 2 using register variables 116700.0 57873095.9 4959.1
Double-Precision Whetstone 55.0 8911.4 1620.3
Execl Throughput 43.0 3441.8 800.4
File Copy 1024 bufsize 2000 maxblocks 3960.0 736707.9 1860.4
File Copy 256 bufsize 500 maxblocks 1655.0 192650.5 1164.1
File Copy 4096 bufsize 8000 maxblocks 5800.0 1852100.6 3193.3
Pipe Throughput 12440.0 1478410.2 1188.4
Pipe-based Context Switching 4000.0 292767.1 731.9
Process Creation 126.0 8627.3 684.7
Shell Scripts (1 concurrent) 42.4 6056.8 1428.5
Shell Scripts (8 concurrent) 6.0 961.9 1603.1
System Call Overhead 15000.0 1108283.9 738.9
========
System Benchmarks Index Score 1372.8参考
What is the runtime performance cost of a Docker container?
I'd like to comprehensively understand the run-time performance cost of a Docker container. I've found references to networking anecdotally being ~100µs slower....
stackoverflow.com
→この記事によるとネットワークコストは50%程度のレイテンシーの低下があるようです。
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