redis: 开启io多线程

一，配置redis.conf

[root@web conf]# vi redis.conf 

修改两个参数

# So for instance if you have a four cores boxes, try to use 2 or 3 I/O
# threads, if you have a 8 cores, try to use 6 threads. In order to
# enable I/O threads use the following configuration directive:
#
# io-threads 4
io-threads 4
#
# Setting io-threads to 1 will just use the main thread as usual.
# When I/O threads are enabled, we only use threads for writes, that is
# to thread the write(2) syscall and transfer the client buffers to the
# socket. However it is also possible to enable threading of reads and
# protocol parsing using the following configuration directive, by setting
# it to yes:
#
# io-threads-do-reads no
io-threads-do-reads yes

二，查看线程数量

启用io多线程前:

[root@web conf]# pstree -p 1569680
redis-server(1569680)─┬─{redis-server}(1569681)
                      ├─{redis-server}(1569682)
                      ├─{redis-server}(1569683)
                      ├─{redis-server}(1569684)
                      └─{redis-server}(1569693)

启用io多线程后:

[root@web conf]# pstree -p 2315378
redis-server(2315378)─┬─{redis-server}(2315380)
                      ├─{redis-server}(2315381)
                      ├─{redis-server}(2315382)
                      ├─{redis-server}(2315383)
                      ├─{redis-server}(2315384)
                      ├─{redis-server}(2315385)
                      └─{redis-server}(2315386)

增加了2个线程，推测有线程是和原来其他的复用，所以没有增加3个

三，从客户端查看配置

修改配置前:

[root@web conf]# redis-cli
127.0.0.1:6379> CONFIG GET * 
253) "io-threads-do-reads"
254) "no"
...
317) "io-threads"
318) "1" 

修改配置后:

[root@web conf]# redis-cli
127.0.0.1:6379> CONFIG GET * 
...
163) "io-threads"
164) "4" 
...
297) "io-threads-do-reads"
298) "yes"