性能工具之stress工具使用教程（帶源碼說明）

安裝stress

stress參數

模擬CPU

模擬內存

模擬磁盤

總結

安裝stress

stress參數

模擬CPU

模擬內存

模擬磁盤

總結

stress是一個在linux下的壓力測試小工具。

我看到有些人用這個工具來描述一些資源耗盡的場景，也有人用它來做混沌測試中。請使用者要注意，這個工具并不是模擬業務問題的，是模擬系統級問題的。所以用它來模擬的時候，和業務真實場景差別還是很大的。

因為在性能工作中，經常有人因為不理解工具而誤用工具，所以這里我把這個工具拿出來說明一下。

安裝stress

yum install -y stress

stress參數

[root@7DGroupT1 ~]# stress `stress' imposes certain types of compute stress on your system Usage: stress [OPTION [ARG]] ... -?, --help show this help statement --version show version statement -v, --verbose be verbose -q, --quiet be quiet -n, --dry-run show what would have been done -t, --timeout N timeout after N seconds --backoff N wait factor of N microseconds before work starts -c, --cpu N spawn N workers spinning on sqrt() -i, --io N spawn N workers spinning on sync() -m, --vm N spawn N workers spinning on malloc()/free() --vm-bytes B malloc B bytes per vm worker (default is 256MB) --vm-stride B touch a byte every B bytes (default is 4096) --vm-hang N sleep N secs before free (default none, 0 is inf) --vm-keep redirty memory instead of freeing and reallocating -d, --hdd N spawn N workers spinning on write()/unlink() --hdd-bytes B write B bytes per hdd worker (default is 1GB) Example: stress --cpu 8 --io 4 --vm 2 --vm-bytes 128M --timeout 10s Note: Numbers may be suffixed with s,m,h,d,y (time) or B,K,M,G (size).

參數可以說非常簡單了。大概看一眼就可以知道，它可以模擬 CPU、IO、內存、磁盤這些常見又重要的資源消耗。

下面就一一來看一下。

模擬CPU

[root@7DGroupT1 ~]# stress -c 4 -t 100

top - 10:48:11 up 63 days, 23:57, 2 users, load average: 0.67, 1.41, 4.21 Tasks: 122 total, 5 running, 117 sleeping, 0 stopped, 0 zombie %Cpu0 : 99.7 us, 0.3 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu1 :100.0 us, 0.0 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu2 :100.0 us, 0.0 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu3 :100.0 us, 0.0 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 8010528 total, 5550792 free, 1866688 used, 593048 buff/cache KiB Swap: 0 total, 0 free, 0 used. 5762564 avail Mem

模擬 CPU 的參數很簡潔。打印一下棧看一下：

[root@s6 ~]# pstack 29253 #0 0x00007f123634761b in random () from /usr/lib64/libc.so.6 #1 0x00007f1236347b39 in rand () from /usr/lib64/libc.so.6 #2 0x0000557e9ea32dbd in hogcpu () #3 0x0000557e9ea3180a in main () [root@s6 ~]

其實代碼很簡單，就是一個 hogcpu 函數。源碼是這樣的：

int hogcpu (void) { while (1) sqrt (rand ()); return 0; }

是不是看了之后覺得自己都能寫一個了？不就是一個 while 嗎？

模擬內存

[root@7DGroupT1 ~]# stress --vm 30 --vm-bytes 1G --vm-hang 50 --timeout 50s

[root@7DGroupT1 ~]# vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 0 0 0 5606796 6828 534736 0 0 4548 212 457 710 0 0 99 1 0 0 0 0 5597852 6976 544360 0 0 9712 52 666 1163 0 0 99 1 0 0 0 0 5595060 7136 545828 0 0 1752 0 440 580 0 0 98 2 0 30 0 0 2125872 7136 546040 0 0 8 0 1098 522 0 21 79 0 0 0 14 0 100896 200 211224 0 0 529748 2932 25058 43164 1 51 4 44 0 [root@7DGroupT1 ~]# sar -B 1 Linux 3.10.0-514.21.1.el7.x86_64 (7DGroupT1) 10/03/2019 _x86_64_ (4 CPU) 10:52:49 AM pgpgin/s pgpgout/s fault/s majflt/s pgfree/s pgscank/s pgscand/s pgsteal/s %vmeff 10:52:50 AM 8.00 68.00 122.00 0.00 1143.00 0.00 0.00 0.00 0.00 10:52:51 AM 0.00 0.00 29.00 0.00 25.00 0.00 0.00 0.00 0.00 10:52:52 AM 0.00 0.00 184.00 0.00 45.00 0.00 0.00 0.00 0.00 10:52:53 AM 0.00 0.00 2482.00 0.00 804.00 0.00 0.00 0.00 0.00 10:52:54 AM 870.77 2436.92 172704.62 2.31 92710.00 38558.46 26820.00 61888.46 94.66 10:52:56 AM 76853.61 618.56 34391.24 82.47 1297422.16 205238.14 404672.68 14717.53 2.41 10:52:57 AM 125560.00 300.00 4875.00 110.00 5040.00 0.00 0.00 0.00 0.00 10:52:58 AM 111080.00 0.00 8940.00 68.00 4723.00 0.00 0.00 0.00 0.00 10:52:59 AM 80944.00 0.00 5725.00 40.00 1636.00 0.00 0.00 0.00 0.00 10:53:00 AM 26224.00 300.00 37293.00 2.00 534.00 0.00 0.00 0.00 0.00 10:53:01 AM 7344.00 180.00 1092.00 0.00 17475.00 0.00 0.00 0.00 0.00 10:53:02 AM 24576.00 224.00 5725.00 41.00 1866.00 0.00 0.00 0.00 0.00 [root@7DGroupT1 ~]# sar -r 1 Linux 3.10.0-514.21.1.el7.x86_64 (7DGroupT1) 10/03/2019 _x86_64_ (4 CPU) 10:56:55 AM kbmemfree kbmemused %memused kbbuffers kbcached kbcommit %commit kbactive kbinact kbdirty 10:57:13 AM 5582520 2428008 30.31 7648 447240 5643636 70.45 1780508 443288 3400 10:57:14 AM 101544 7908984 98.73 6736 375896 37108100 463.24 7328268 367028 3404

從上面的數據來看，確實產生了很大的 page faults，這也是模擬內存消耗的過程中必然會出現的現象。之前我也強調過，看內存夠不夠，就是要看這個 faluts。

在 Stress 中，怎么模擬的內存呢。來看一下。

int hogvm (long long bytes, long long stride, long long hang, int keep) { long long i; char *ptr = 0; char c; int do_malloc = 1; while (1) { if (do_malloc) { dbg (stdout, "allocating %lli bytes ...\n", bytes); if (!(ptr = (char *) malloc (bytes * sizeof (char)))) { err (stderr, "hogvm malloc failed: %s\n", strerror (errno)); return 1; } if (keep) do_malloc = 0; } dbg (stdout, "touching bytes in strides of %lli bytes ...\n", stride); for (i = 0; i < bytes; i += stride) ptr[i] = 'Z'; /* Ensure that COW happens. */ if (hang == 0) { dbg (stdout, "sleeping forever with allocated memory\n"); while (1) sleep (1024); } else if (hang > 0) { dbg (stdout, "sleeping for %llis with allocated memory\n", hang); sleep (hang); } for (i = 0; i < bytes; i += stride) { c = ptr[i]; if (c != 'Z') { err (stderr, "memory corruption at: %p\n", ptr + i); return 1; } } if (do_malloc) { free (ptr); dbg (stdout, "freed %lli bytes\n", bytes); } } return 0; }

就是一個死循環加上一個內存 malloc。

模擬磁盤

[root@7DGroupT1 ~]# stress --hdd 5 --hdd-bytes 1G

[root@7DGroupT1 ~]# top top - 10:35:15 up 63 days, 23:44, 2 users, load average: 9.14, 8.49, 8.29 Tasks: 124 total, 2 running, 122 sleeping, 0 stopped, 0 zombie %Cpu0 : 0.0 us, 5.8 sy, 0.0 ni, 0.0 id, 94.2 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu1 : 1.0 us, 1.0 sy, 0.0 ni, 14.4 id, 83.6 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu2 : 0.0 us, 4.4 sy, 0.0 ni, 0.0 id, 95.6 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu3 : 0.0 us, 4.1 sy, 0.0 ni, 0.0 id, 95.9 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 8010528 total, 1940088 free, 1891792 used, 4178648 buff/cache KiB Swap: 0 total, 0 free, 0 used. 5687416 avail Mem [root@7DGroupT1 ~]# vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 1 7 0 1474132 146392 4499176 0 0 0 12 0 1 0 0 100 0 0 0 7 0 1384720 146392 4589204 0 0 0 107624 815 966 0 3 8 88 0 0 7 0 1292432 146392 4681232 0 0 0 98920 1036 987 0 3 13 84 0 0 7 0 1194932 146392 4777968 0 0 0 115344 1033 1207 0 4 0 96 0 1 6 0 1094312 146392 4880044 0 0 0 105260 928 930 0 3 5 92 0 1 6 0 998756 146416 4974944 0 0 0 102812 862 928 0 3 0 97 0 0 7 0 897960 146448 5075492 0 0 0 131200 1268 1565 1 4 5 91 0 3 4 0 1626628 146472 4347076 0 0 0 82804 1444 1206 0 8 10 81 0 0 7 0 2354208 146656 3620344 0 0 0 118112 2229 1256 0 27 2 70 0 0 7 0 3264136 146804 2709776 0 0 0 110632 1761 1506 0 9 0 90 0 0 7 0 3143120 146940 2831728 0 0 4 106896 1211 1112 0 5 0 95 0 0 7 0 2961456 146940 3016064 0 0 0 91456 1484 1298 0 6 0 94 0 ^C [root@7DGroupT1 ~]# sar -d 1 10:54:19 AM DEV tps rd_sec/s wr_sec/s avgrq-sz avgqu-sz await svctm %util 10:54:20 AM dev253-0 307.00 24.00 229976.00 749.19 126.47 454.24 3.26 100.00 10:54:20 AM dev11-0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10:54:20 AM DEV tps rd_sec/s wr_sec/s avgrq-sz avgqu-sz await svctm %util 10:54:21 AM dev253-0 369.00 48.00 228528.00 619.45 127.11 347.24 2.71 100.00 10:54:21 AM dev11-0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10:54:21 AM DEV tps rd_sec/s wr_sec/s avgrq-sz avgqu-sz await svctm %util 10:54:22 AM dev253-0 274.00 24.00 203760.00 743.74 127.45 404.61 3.65 100.00 10:54:22 AM dev11-0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10:54:22 AM DEV tps rd_sec/s wr_sec/s avgrq-sz avgqu-sz await svctm %util 10:54:23 AM dev253-0 262.00 0.00 202000.00 770.99 127.61 486.35 3.82 100.10 10:54:23 AM dev11-0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10:54:23 AM DEV tps rd_sec/s wr_sec/s avgrq-sz avgqu-sz await svctm %util 10:54:24 AM dev253-0 288.00 0.00 232352.00 806.78 127.92 479.62 3.47 100.00 10:54:24 AM dev11-0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 [root@7DGroupT1 ~]# iostat -x -d 1 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util vda 0.00 8603.00 4.00 255.00 16.00 101840.00 786.53 125.75 471.71 3.00 479.06 3.86 100.00 scd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util vda 0.00 8952.00 4.00 294.00 16.00 117176.00 786.52 127.03 470.79 3.75 477.14 3.36 100.00 scd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util vda 0.00 9059.00 1.00 266.00 4.00 101900.00 763.33 126.55 433.52 0.00 435.15 3.75 100.00 scd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util vda 0.00 6234.00 0.00 273.00 0.00 96784.00 709.04 127.94 391.18 0.00 391.18 3.67 100.10 scd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 [root@7DGroupT1 ~]# iotop Total DISK READ : 0.00 B/s | Total DISK WRITE : 102.23 M/s Actual DISK READ: 0.00 B/s | Actual DISK WRITE: 75.93 M/s TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND 8681 be/4 root 0.00 B/s 20.93 M/s 0.00 % 98.97 % stress --hdd 5 --hdd-bytes 1G 8677 be/4 root 0.00 B/s 20.23 M/s 0.00 % 95.92 % stress --hdd 5 --hdd-bytes 1G 8680 be/4 root 0.00 B/s 20.23 M/s 0.00 % 95.59 % stress --hdd 5 --hdd-bytes 1G 8679 be/4 root 0.00 B/s 20.61 M/s 0.00 % 95.17 % stress --hdd 5 --hdd-bytes 1G 8678 be/4 root 0.00 B/s 20.23 M/s 0.00 % 95.16 % stress --hdd 5 --hdd-bytes 1G 7298 be/4 root 0.00 B/s 0.00 B/s 0.00 % 86.91 % [kworker/u8:1] 285 be/3 root 0.00 B/s 0.00 B/s 0.00 % 86.72 % [jbd2/vda1-8] 16384 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % YDService 1 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % systemd --syst~deserialize 21 2 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kthreadd] 3 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [ksoftirqd/0] 516 be/4 libstora 0.00 B/s 0.00 B/s 0.00 % 0.00 % lsmd -d 5 be/0 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kworker/0:0H] 518 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % acpid 7 rt/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [migration/0] 8 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [rcu_bh] 9 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [rcu_sched] 10 rt/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [watchdog/0] 11 rt/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [watchdog/1] 12 rt/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [migration/1] 13 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [ksoftirqd/1] 526 be/4 polkitd 0.00 B/s 0.00 B/s 0.00 % 0.00 % polkitd --no-d~ Sour~ Thread] 15 be/0 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kworker/1:0H] 16 rt/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [watchdog/2] 17 rt/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [migration/2] 18 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [ksoftirqd/2] 515 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % python -Es /us~in/tuned -l -P 20 be/0 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kworker/2:0H] 21 rt/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [watchdog/3] 22 rt/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [migration/3] 23 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [ksoftirqd/3] 25 be/0 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kworker/3:0H] 27 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kdevtmpfs] 28 be/0 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [netns] 29 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [khungtaskd] 30 be/0 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [writeback]

模擬磁盤，看起來效果也是非常不錯的哦。來翻一下源碼。

int hoghdd (long long bytes) { long long i, j; int fd; int chunk = (1024 * 1024) - 1; /* Minimize slow writing. */ char buff[chunk]; /* Initialize buffer with some random ASCII data. */ dbg (stdout, "seeding %d byte buffer with random data\n", chunk); for (i = 0; i < chunk - 1; i++) { j = rand (); j = (j < 0) ? -j : j; j %= 95; j += 32; buff[i] = j; } buff[i] = '\n'; while (1) { char name[] = "./stress.XXXXXX"; if ((fd = mkstemp (name)) == -1) { err (stderr, "mkstemp failed: %s\n", strerror (errno)); return 1; } dbg (stdout, "opened %s for writing %lli bytes\n", name, bytes); dbg (stdout, "unlinking %s\n", name); if (unlink (name) == -1) { err (stderr, "unlink of %s failed: %s\n", name, strerror (errno)); return 1; } dbg (stdout, "fast writing to %s\n", name); for (j = 0; bytes == 0 || j + chunk < bytes; j += chunk) { if (write (fd, buff, chunk) == -1) { err (stderr, "write failed: %s\n", strerror (errno)); return 1; } } dbg (stdout, "slow writing to %s\n", name); for (; bytes == 0 || j < bytes - 1; j++) { if (write (fd, &buff[j % chunk], 1) == -1) { err (stderr, "write failed: %s\n", strerror (errno)); return 1; } } if (write (fd, "\n", 1) == -1) { err (stderr, "write failed: %s\n", strerror (errno)); return 1; } ++j; dbg (stdout, "closing %s after %lli bytes\n", name, j); close (fd); } return 0; }

死循環加上 for 循環不斷的調用 write。這個調用，就是不停地做寫的動作。這個和我們在上面看到的監控數據也是一致的。

總結

總結一下，通過這些源碼說明，請你在使用的時候，要注意一下，像這樣的工具，如果說只是為了單純地消耗系統級的資源，然后觀察應用在較少的可用資源下的表現如何，這樣的工具是可以用的。

但是如果是想要模擬你的業務層出現的問題，那我勸你還是別用這樣的工具了。

Linux 云性能測試服務 CPTS 應用性能調優

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