转载----How fast is Redis?

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How fast is Redis?
　　Redis includes the redis-benchmark utility that simulates running commands done by N clients at the same time sending M total queries (it is similar to the Apache's ab utility). Below you'll find the full output of a benchmark executed against a Linux box.
　　The following options are supported:

Usage: redis-benchmark [-h ] [-p ] [-c ] [-n  [-k ]
-h       Server hostname (default 127.0.0.1)
-p           Server port (default 6379)
-s         Server socket (overrides host and port)
-c        Number of parallel connections (default 50)
-n       Total number of requests (default 10000)
-d           Data size of SET/GET value in bytes (default 2)
-k        1=keep alive 0=reconnect (default 1)
-r    Use random keys for SET/GET/INCR, random values for SADD
Using this option the benchmark will get/set keys
in the form mykey_rand:000000012456 instead of constant
keys, the  argument determines the max
number of values for the random number. For instance
if set to 10 only rand:000000000000 - rand:000000000009
range will be allowed.
-P         Pipeline  requests. Default 1 (no pipeline).
-q                 Quiet. Just show query/sec values
--csv              Output in CSV format
-l                 Loop. Run the tests forever
-t          Only run the comma separated list of tests. The test
names are the same as the ones produced as output.
-I                 Idle mode. Just open N idle connections and wait.

　　You need to have a running Redis instance before launching the benchmark. A typical example would be:

redis-benchmark -q -n 100000

　　Using this tool is quite easy, and you can also write your own benchmark, but as with any benchmarking activity, there are some pitfalls to avoid.

Running only a subset of the tests
　　You don't need to run all the default tests every time you execute redis-benchmark. The simplest thing to select only a subset of tests is to use the -t option like in the following example:

$ redis-benchmark -t set,lpush -n 100000 -q
SET: 74239.05 requests per second
LPUSH: 79239.30 requests per second

　　In the above example we asked to just run test the SET and LPUSH commands, in quite mode (see the -q switch).
　　It is also possible to specify the command to benchmark directly like in the following example:

$ redis-benchmark -n 100000 -q script load "redis.call('set','foo','bar')"
script load redis.call('set','foo','bar'): 69881.20 requests per second

Selecting the size of the key space
　　By default the benchmark runs against a single key. In Redis the difference between such a synthetic benchmark and a real one is not huge since it is an in memory system, however it is possible to stress cache misses and in general to simulate a more real-world work load by using a large key space.
　　This is obtained by using the -r switch. For instance if I want to run one million of SET operations, using a random key for every operation out of 100k possible keys, I'll use the following command line:

$ redis-cli flushall
OK
$ redis-benchmark -t set -r 100000 -n 1000000
====== SET ======
1000000 requests completed in 13.86 seconds
50 parallel clients
3 bytes payload
keep alive: 1
99.76% `