(十三)— redis-benchmark性能测试
最后更新于:2022-04-01 20:20:40
今天讲的这个是用来给redis数据库做性能测试的,说到性能测试,感觉这必然是高大上的操作了,redis性能测试,测的到底是哪方面的性能,如何测试,通过什么指标反映此次测试的性能好坏呢,下面我通过源码给大家做一一解答。
redis做的性能测试时对立面的基本操作做的检测,比如Client客户端执行set,get,lpush等数据操作的性能,可以从他的测试程序可以看出:
~~~
if (test_is_selected("get")) {
len = redisFormatCommand(&cmd,"GET key:__rand_int__");
benchmark("GET",cmd,len);
free(cmd);
}
if (test_is_selected("incr")) {
len = redisFormatCommand(&cmd,"INCR counter:__rand_int__");
benchmark("INCR",cmd,len);
free(cmd);
}
if (test_is_selected("lpush")) {
len = redisFormatCommand(&cmd,"LPUSH mylist %s",data);
benchmark("LPUSH",cmd,len);
free(cmd);
}
if (test_is_selected("lpop")) {
len = redisFormatCommand(&cmd,"LPOP mylist");
benchmark("LPOP",cmd,len);
free(cmd);
}
~~~
那么通过什么指标反映测试性能的好坏之分呢,在这里我们使用的就是延时性来判断,最简单的想法,就是在测试到额最开始,记录一个时间,中间执行测试操作,在操作结束在记录一个时间,中间的时间差就是执行的时间,时间越短说明性能越好。这也正是redis性能测试的做法。
~~~
/* 对指定的CMD命令做性能测试 */
static void benchmark(char *title, char *cmd, int len) {
client c;
config.title = title;
config.requests_issued = 0;
config.requests_finished = 0;
c = createClient(cmd,len,NULL);
createMissingClients(c);
config.start = mstime();
aeMain(config.el);
//最后通过计算总延时,显示延时报告,体现性能测试的结果
config.totlatency = mstime()-config.start;
showLatencyReport();
freeAllClients();
}
~~~
因为这样的操作要求时间精度比较高,用秒做单位肯定不行了,所以这里用的是ms毫秒,在这里添加个知识点,在这里用到了时间相关的结构体,在Linux里也存在:
~~~
/* 介绍一下struct timeval结构体
struct timeval结构体在time.h中的定义为:
struct timeval
{
__time_t tv_sec; // Seconds.
__suseconds_t tv_usec; // Microseconds. (微秒)
}; */
~~~
那么下面是最关键的问题了,如何测,测试肯定要通过一个模拟客户端,按照配置文件中的设置去测试,所以必须存在一个配置信息,然后我们通过我们想要的配置再去逐步测试,亮出config,配置信息:
~~~
/* config配置信息结构体,static静态变量,使得全局只有一个 */
static struct config {
//消息事件
aeEventLoop *el;
const char *hostip;
int hostport;
//据此判断是否是本地测试
const char *hostsocket;
//Client总数量
int numclients;
int liveclients;
//请求的总数
int requests;
int requests_issued;
//请求完成的总数
int requests_finished;
int keysize;
int datasize;
int randomkeys;
int randomkeys_keyspacelen;
int keepalive;
int pipeline;
long long start;
long long totlatency;
long long *latency;
const char *title;
//Client列表,这个在下面会经常提起
list *clients;
int quiet;
int csv;
//判断是否loop循环处理
int loop;
int idlemode;
int dbnum;
sds dbnumstr;
char *tests;
char *auth;
} config;
typedef struct _client {
//redis上下文
redisContext *context;
//此缓冲区将用于后面的读写handler
sds obuf;
//rand指针数组
char **randptr; /* Pointers to :rand: strings inside the command buf */
//randptr中指针个数
size_t randlen; /* Number of pointers in client->randptr */
//randptr中没有被使用的指针个数
size_t randfree; /* Number of unused pointers in client->randptr */
unsigned int written; /* Bytes of 'obuf' already written */
//请求的发起时间
long long start; /* Start time of a request */
//请求的延时
long long latency; /* Request latency */
//请求的等待个数
int pending; /* Number of pending requests (replies to consume) */
int selectlen; /* If non-zero, a SELECT of 'selectlen' bytes is currently
used as a prefix of the pipline of commands. This gets
discarded the first time it's sent. */
} *client;
~~~
上面还附带了client的一些信息,这里的Client和之前的RedisClient还不是一个东西,也就是说,这里的Client会根据config结构体中的配置做相应的操作。client根据获得到命令无非2种操作,read和Write,所以在后面的事件处理中也是针对这2种事件的处理,这里给出read的方法:
~~~
/* 读事件的处理方法 */
static void readHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
client c = privdata;
void *reply = NULL;
REDIS_NOTUSED(el);
REDIS_NOTUSED(fd);
REDIS_NOTUSED(mask);
/* Calculate latency only for the first read event. This means that the
* server already sent the reply and we need to parse it. Parsing overhead
* is not part of the latency, so calculate it only once, here. */
//计算延时,然后比较延时,取得第一个read 的event事件
if (c->latency < 0) c->latency = ustime()-(c->start);
if (redisBufferRead(c->context) != REDIS_OK) {
//首先判断能否读
fprintf(stderr,"Error: %s\n",c->context->errstr);
exit(1);
} else {
while(c->pending) {
if (redisGetReply(c->context,&reply) != REDIS_OK) {
fprintf(stderr,"Error: %s\n",c->context->errstr);
exit(1);
}
if (reply != NULL) {
//获取reply回复,如果这里出错,也会直接退出
if (reply == (void*)REDIS_REPLY_ERROR) {
fprintf(stderr,"Unexpected error reply, exiting...\n");
exit(1);
}
freeReplyObject(reply);
if (c->selectlen) {
size_t j;
/* This is the OK from SELECT. Just discard the SELECT
* from the buffer. */
//执行到这里,请求已经执行成功,等待的请求数减1
c->pending--;
sdsrange(c->obuf,c->selectlen,-1);
/* We also need to fix the pointers to the strings
* we need to randomize. */
for (j = 0; j < c->randlen; j++)
c->randptr[j] -= c->selectlen;
c->selectlen = 0;
continue;
}
if (config.requests_finished < config.requests)
config.latency[config.requests_finished++] = c->latency;
c->pending--;
if (c->pending == 0) {
//调用客户端done完成后的方法
clientDone(c);
break;
}
} else {
break;
}
}
}
}
~~~
这个方法其实是一个回调方法,会作为参数传入另一个函数中,redis的函数式编程的思想又再次体现了,在这些操作都执行好了之后,会有个延时报告,针对各种操作的延时统计,这时我们就能知道,性能之间的比较了:
~~~
/* 输出请求延时 */
static void showLatencyReport(void) {
int i, curlat = 0;
float perc, reqpersec;
reqpersec = (float)config.requests_finished/((float)config.totlatency/1000);
if (!config.quiet && !config.csv) {
printf("====== %s ======\n", config.title);
printf(" %d requests completed in %.2f seconds\n", config.requests_finished,
(float)config.totlatency/1000);
printf(" %d parallel clients\n", config.numclients);
printf(" %d bytes payload\n", config.datasize);
printf(" keep alive: %d\n", config.keepalive);
printf("\n");
//将请求按延时排序
qsort(config.latency,config.requests,sizeof(long long),compareLatency);
for (i = 0; i < config.requests; i++) {
if (config.latency[i]/1000 != curlat || i == (config.requests-1)) {
curlat = config.latency[i]/1000;
perc = ((float)(i+1)*100)/config.requests;
printf("%.2f%% <= %d milliseconds\n", perc, curlat);
}
}
printf("%.2f requests per second\n\n", reqpersec);
} else if (config.csv) {
printf("\"%s\",\"%.2f\"\n", config.title, reqpersec);
} else {
printf("%s: %.2f requests per second\n", config.title, reqpersec);
}
}
~~~
当然你能更改配置文件,做你想做的性能测试,不过这里我想吐槽一点,这么多个if判断语句不是很好吧,换成switch也比这简洁啊:
~~~
/* Returns number of consumed options. */
/* 根据读入的参数,设置config配置文件 */
int parseOptions(int argc, const char **argv) {
int i;
int lastarg;
int exit_status = 1;
for (i = 1; i < argc; i++) {
lastarg = (i == (argc-1));
//通过多重if判断,但个人感觉不够优美,稳定性略差
if (!strcmp(argv[i],"-c")) {
if (lastarg) goto invalid;
config.numclients = atoi(argv[++i]);
} else if (!strcmp(argv[i],"-n")) {
if (lastarg) goto invalid;
config.requests = atoi(argv[++i]);
} else if (!strcmp(argv[i],"-k")) {
if (lastarg) goto invalid;
config.keepalive = atoi(argv[++i]);
} else if (!strcmp(argv[i],"-h")) {
if (lastarg) goto invalid;
config.hostip = strdup(argv[++i]);
} else if (!strcmp(argv[i],"-p")) {
if (lastarg) goto invalid;
config.hostport = atoi(argv[++i]);
} else if (!strcmp(argv[i],"-s")) {
if (lastarg) goto invalid;
config.hostsocket = strdup(argv[++i]);
} else if (!strcmp(argv[i],"-a") ) {
if (lastarg) goto invalid;
config.auth = strdup(argv[++i]);
} else if (!strcmp(argv[i],"-d")) {
if (lastarg) goto invalid;
config.datasize = atoi(argv[++i]);
if (config.datasize < 1) config.datasize=1;
if (config.datasize > 1024*1024*1024) config.datasize = 1024*1024*1024;
} else if (!strcmp(argv[i],"-P")) {
if (lastarg) goto invalid;
config.pipeline = atoi(argv[++i]);
//......省略
~~~
redis的性能测试还能支持本地测试和指定Ip,端口测试,挺方便的。下面列出全部的API:
~~~
/* Prototypes */
/* 方法原型 */
static void createMissingClients(client c); /* 创建没有Command命令要求的clint */
static long long ustime(void) /* 返回当期时间的单位为微秒的格式 */
static long long mstime(void) /* 返回当期时间的单位为毫秒的格式 */
static void freeClient(client c) /* 释放Client */
static void freeAllClients(void) /* 释放所有的Client */
static void resetClient(client c) /* 重置Client */
static void randomizeClientKey(client c) /* 随机填充client里的randptr中的key值 */
static void clientDone(client c) /* Client完成后的调用方法 */
static void readHandler(aeEventLoop *el, int fd, void *privdata, int mask) /* 读事件的处理方法 */
static void writeHandler(aeEventLoop *el, int fd, void *privdata, int mask) /* 写事件方法处理 */
static client createClient(char *cmd, size_t len, client from) /* 创建一个基准的Client */
static int compareLatency(const void *a, const void *b) /* 比较延时 */
static void showLatencyReport(void) /* 输出请求延时 */
static void benchmark(char *title, char *cmd, int len) /* 对指定的CMD命令做性能测试 */
int parseOptions(int argc, const char **argv) /* 根据读入的参数,设置config配置文件 */
int showThroughput(struct aeEventLoop *eventLoop, long long id, void *clientData) /* 显示Request执行的速度,简称RPS */
int test_is_selected(char *name) /* 检测config中的命令是否被选中 */
~~~
';