setting RCC of STM32F103

Hi, I have set PLL of STM32F103RE chip with the following function to 36Mhz, but the operation frequency is much lower??

void Config_clock(void)
{
  /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration -----------------------------*/
  /* RCC system reset(for debug purpose) */
  RCC_DeInit();

  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);

  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();

  if(HSEStartUpStatus == SUCCESS)
  {
    /* Enable Prefetch Buffer */
    FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

    /* Flash 2 wait state */
    FLASH_SetLatency(FLASH_Latency_2);



   RCC_PLLConfig(RCC_PLLSource_HSI_Div2, RCC_PLLMul_9);//36Mhz

    /* Enable PLL */
    RCC_PLLCmd(ENABLE);

    /* Wait till PLL is ready */
    while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
    {
    }

    /* Select PLL as system clock source */
    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

        /* Set HCLK, PCLK1, and PCLK2 to SCLK (these are default */
  RCC_HCLKConfig(RCC_SYSCLK_Div1);
  RCC_PCLK1Config(RCC_HCLK_Div1);
  RCC_PCLK2Config(RCC_HCLK_Div1);

    /* Wait till PLL is used as system clock source */
    while(RCC_GetSYSCLKSource() != 0x08)
    {
    }
      /* Enable USART1 and GPIOA clock */
     RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);
  }

  /* Enable GPIOA, GPIOB, GPIOC, GPIOD, GPIOE, GPIOF, GPIOG and AFIO clocks */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB |RCC_APB2Periph_GPIOC
         | RCC_APB2Periph_GPIOD | RCC_APB2Periph_GPIOE | RCC_APB2Periph_GPIOF | RCC_APB2Periph_GPIOG
         | RCC_APB2Periph_AFIO, ENABLE);

/*------------------- Resources Initialization -----------------------------*/
     /* ADCCLK = PCLK2/8 */
   RCC_ADCCLKConfig(RCC_PCLK2_Div8);

    /* Enable DMA clock */
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

   /* Enable ADC1 and GPIOC clock */
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_ALL, ENABLE);

   RCC_APB1PeriphClockCmd(RCC_APB1Periph_ALL, ENABLE);

  /* If HSE is not detected at program startup */
  if(HSEStartUpStatus == ERROR)
  {
    /* Generate NMI exception */
    NVIC_SetSystemHandlerPendingBit(SystemHandler_NMI);
  }


}