update readme. 10k clients.

@@ -729,6 +729,7 @@ The play benchmark by [st-load](https://github.com/winlinvip/st-load):
 * 2014-11-22, SRS 2.0.30,  7.5k(7500)clients, 87%CPU, 320MB. [commit](https://github.com/winlinvip/simple-rtmp-server/commit/58136ec178e3d47db6c90a59875d7e40946936e5)
 * 2014-12-05, SRS 2.0.55,  8.0k(8000)clients, 89%CPU, 360MB. (mw_sleep=350)[commit](https://github.com/winlinvip/simple-rtmp-server/commit/58136ec178e3d47db6c90a59875d7e40946936e5)
 * 2014-12-05, SRS 2.0.57,  9.0k(9000)clients, 90%CPU, 468MB. [commit](https://github.com/winlinvip/simple-rtmp-server/commit/9ee138746f83adc26f0e236ec017f4d68a300004)
+* 2014-12-07, SRS 2.0.67,  10k(10000)clients, 95%CPU, 656MB. [commit](https://github.com/winlinvip/simple-rtmp-server/commit/1311b6fe6576fd7b9c6d299b0f8f2e8d202f4bf8)
 
 ### Publish benchmark