I am concentrating only on Accelerometer data from MPU9250, I have disabled Gyro and Magneto for faster communication. I am able to capture 177 samples per second (1 sample has 6 bytes). I am targeting to achieve 4KHz sampling rate (means 4000*6 = 24000 bytes per second). I am generating interrupt of 250 microsecond, also i am writing 0 in register 29 bit[3], DLPF will suppose to be bypassed and rate should be 4KHz. In my case it is (177 samples) nowhere corelated with 4KHz sampling Rate. I am not finding invensense datasheet useful for my case as i have strictly followed it but did not get expected result. I want to create efficient algorithm for FALL DETECTION as i need some graphical approach on accelero data (should be at maximum sampling rate i.e 4K). I want to go ahead with I2C protocol for same.