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Microsecond latency resolution in redis-benchmark

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1 parent ec8f066 commit 8146e31677f29440854edd310adfc521a6e65bad @pietern pietern committed Nov 4, 2010
Showing with 40 additions and 28 deletions.
  1. +40 −28 src/redis-benchmark.c
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@@ -45,17 +45,10 @@
#include "adlist.h"
#include "zmalloc.h"
-#define REPLY_INT 0
-#define REPLY_RETCODE 1
-#define REPLY_BULK 2
-#define REPLY_MBULK 3
-
#define CLIENT_CONNECTING 0
#define CLIENT_SENDQUERY 1
#define CLIENT_READREPLY 2
-#define MAX_LATENCY 5000
-
#define REDIS_NOTUSED(V) ((void) V)
static struct config {
@@ -75,7 +68,7 @@ static struct config {
int keepalive;
long long start;
long long totlatency;
- int *latency;
+ long long *latency;
char *title;
list *clients;
int quiet;
@@ -87,16 +80,27 @@ typedef struct _client {
redisContext *context;
int state;
sds obuf;
- unsigned int written; /* bytes of 'obuf' already written */
+ unsigned int written; /* bytes of 'obuf' already written */
int replytype;
- long long start; /* start time in milliseconds */
+ long long start; /* start time of a request */
+ long long latency; /* request latency */
} *client;
/* Prototypes */
static void writeHandler(aeEventLoop *el, int fd, void *privdata, int mask);
static void createMissingClients(client c);
/* Implementation */
+static long long ustime(void) {
+ struct timeval tv;
+ long long ust;
+
+ gettimeofday(&tv, NULL);
+ ust = ((long)tv.tv_sec)*1000000;
+ ust += tv.tv_usec;
+ return ust;
+}
+
static long long mstime(void) {
struct timeval tv;
long long mst;
@@ -136,7 +140,8 @@ static void resetClient(client c) {
aeCreateFileEvent(config.el,c->context->fd,AE_WRITABLE,writeHandler,c);
c->written = 0;
c->state = CLIENT_SENDQUERY;
- c->start = mstime();
+ c->start = ustime();
+ c->latency = -1;
}
static void randomizeClientKey(client c) {
@@ -153,12 +158,6 @@ static void randomizeClientKey(client c) {
}
static void clientDone(client c) {
- long long latency;
- config.donerequests ++;
- latency = mstime() - c->start;
- if (latency > MAX_LATENCY) latency = MAX_LATENCY;
- config.latency[latency]++;
-
if (config.donerequests == config.requests) {
freeClient(c);
aeStop(config.el);
@@ -182,6 +181,11 @@ static void readHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
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. */
+ if (c->latency < 0) c->latency = ustime()-(c->start);
+
if (redisBufferRead(c->context) != REDIS_OK) {
fprintf(stderr,"Error: %s\n",c->context->errstr);
exit(1);
@@ -190,8 +194,11 @@ static void readHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
fprintf(stderr,"Error: %s\n",c->context->errstr);
exit(1);
}
- if (reply != NULL)
+ if (reply != NULL) {
+ if (config.donerequests < config.requests)
+ config.latency[config.donerequests++] = c->latency;
clientDone(c);
+ }
}
}
@@ -203,7 +210,8 @@ static void writeHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
if (c->state == CLIENT_CONNECTING) {
c->state = CLIENT_SENDQUERY;
- c->start = mstime();
+ c->start = ustime();
+ c->latency = -1;
}
if (sdslen(c->obuf) > c->written) {
void *ptr = c->obuf+c->written;
@@ -258,8 +266,12 @@ static void createMissingClients(client c) {
}
}
+static int compareLatency(const void *a, const void *b) {
+ return (*(long long*)a)-(*(long long*)b);
+}
+
static void showLatencyReport(void) {
- int j, seen = 0;
+ int i, curlat = 0;
float perc, reqpersec;
reqpersec = (float)config.donerequests/((float)config.totlatency/1000);
@@ -271,11 +283,13 @@ static void showLatencyReport(void) {
printf(" %d bytes payload\n", config.datasize);
printf(" keep alive: %d\n", config.keepalive);
printf("\n");
- for (j = 0; j <= MAX_LATENCY; j++) {
- if (config.latency[j]) {
- seen += config.latency[j];
- perc = ((float)seen*100)/config.donerequests;
- printf("%.2f%% <= %d milliseconds\n", perc, j);
+
+ 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);
@@ -285,7 +299,6 @@ static void showLatencyReport(void) {
}
static void prepareForBenchmark(char *title) {
- memset(config.latency,0,sizeof(int)*(MAX_LATENCY+1));
config.title = title;
config.start = mstime();
config.donerequests = 0;
@@ -400,13 +413,12 @@ int main(int argc, char **argv) {
config.idlemode = 0;
config.latency = NULL;
config.clients = listCreate();
- config.latency = zmalloc(sizeof(int)*(MAX_LATENCY+1));
-
config.hostip = "127.0.0.1";
config.hostport = 6379;
config.hostsocket = NULL;
parseOptions(argc,argv);
+ config.latency = zmalloc(sizeof(long long)*config.requests);
if (config.keepalive == 0) {
printf("WARNING: keepalive disabled, you probably need 'echo 1 > /proc/sys/net/ipv4/tcp_tw_reuse' for Linux and 'sudo sysctl -w net.inet.tcp.msl=1000' for Mac OS X in order to use a lot of clients/requests\n");

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