diff --git a/README.md b/README.md
index 06fdde0a7..e344241d7 100755
--- a/README.md
+++ b/README.md
@@ -562,6 +562,7 @@ Supported operating systems and hardware:
 
 ### SRS 2.0 history
 
+* v2.0, 2015-05-22, fix [#397](https://github.com/simple-rtmp-server/srs/issues/397) the USER_HZ maybe not 100. 2.0.165
 * v2.0, 2015-05-22, for [#400](https://github.com/simple-rtmp-server/srs/issues/400), parse when got entire http header, by feilong. 2.0.164.
 * v2.0, 2015-05-19, merge from bravo system, add the rtmfp to bms(commercial srs). 2.0.163.
 * v2.0, 2015-05-10, support push flv stream over HTTP POST to SRS.
@@ -672,6 +673,10 @@ Supported operating systems and hardware:
 
 ### SRS 1.0 history
 
+* v1.0, 2015-05-22, fix [#397](https://github.com/simple-rtmp-server/srs/issues/397) the USER_HZ maybe not 100. 1.0.32
+* v1.0, 2015-03-26, fix hls aac adts bug, in aac mux. 1.0.31.
+* <strong>v1.0, 2015-03-19, [1.0r3 release(1.0.30)](https://github.com/simple-rtmp-server/srs/releases/tag/1.0r3) released. 59511 lines.</strong>
+* v1.0, 2015-03-17, remove the osx for 1.0.30.
 * v1.0, 2015-02-17, the join maybe failed, should use a variable to ensure thread terminated. 1.0.28.
 * <strong>v1.0, 2015-02-12, [1.0r2 release(1.0.27)](https://github.com/simple-rtmp-server/srs/releases/tag/1.0r2) released. 59507 lines.</strong>
 * v1.0, 2015-02-11, dev code HuKaiqun for 1.0.27.
diff --git a/trunk/src/app/srs_app_utility.cpp b/trunk/src/app/srs_app_utility.cpp
index fc1d81237..9c7ef3d47 100644
--- a/trunk/src/app/srs_app_utility.cpp
+++ b/trunk/src/app/srs_app_utility.cpp
@@ -418,15 +418,13 @@ bool get_proc_self_stat(SrsProcSelfStat& r)
 
 void srs_update_proc_stat()
 {
-    // always assert the USER_HZ is 1/100ths
     // @see: http://stackoverflow.com/questions/7298646/calculating-user-nice-sys-idle-iowait-irq-and-sirq-from-proc-stat/7298711
-    static bool user_hz_assert = false;
-    if (!user_hz_assert) {
-        user_hz_assert = true;
-        
-        int USER_HZ = sysconf(_SC_CLK_TCK);
-        srs_trace("USER_HZ=%d", USER_HZ);
-        srs_assert(USER_HZ == 100);
+    // @see https://github.com/simple-rtmp-server/srs/issues/397
+    static int user_hz = 0;
+    if (user_hz <= 0) {
+        user_hz = sysconf(_SC_CLK_TCK);
+        srs_trace("USER_HZ=%d", user_hz);
+        srs_assert(user_hz > 0);
     }
     
     // system cpu stat
@@ -471,7 +469,7 @@ void srs_update_proc_stat()
         int64_t total = r.sample_time - o.sample_time;
         int64_t usage = (r.utime + r.stime) - (o.utime + o.stime);
         if (total > 0) {
-            r.percent = (float)(usage * 1000 / (double)total / 100);
+            r.percent = (float)(usage * 1000 / (double)total / user_hz);
         }
         
         // upate cache.
diff --git a/trunk/src/core/srs_core.hpp b/trunk/src/core/srs_core.hpp
index 775ca8f10..433f07139 100644
--- a/trunk/src/core/srs_core.hpp
+++ b/trunk/src/core/srs_core.hpp
@@ -31,7 +31,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // current release version
 #define VERSION_MAJOR       2
 #define VERSION_MINOR       0
-#define VERSION_REVISION    164
+#define VERSION_REVISION    165
 
 // server info.
 #define RTMP_SIG_SRS_KEY "SRS"