RDP bitmap hash acceleration using SIMD instructions

摘要

Systems, methods and computer readable media are disclosed for a vectorized tile differencing algorithm for a remote desktop protocol (RDP). A server executes a CBC-variant vectorized hash algorithm that is used to produce a big key that identifies the tile, and keeps track of these big keys. Where a serial version of the algorithm operates on a single portion of the image at once—such as 32 bits—the vectorized algorithm operates on a plurality of these portions simultaneously. Where the server identifies that a tile has already been sent to a client via RDP because it has a second big key that matches the big key, it sends the big key to the client—which caches received tiles—and the client uses it to access the proper tile for display. Where the server identifies that a tile has not already been sent to the client, it sends the client the tile.

主权项

1. A computer-implemented method for classifying an image on a parallel processing system having a bit width corresponding to a number of bits that a processor of the parallel processing system may operate on at a time, the method involving a first random number and a second random number, the first random number differing from the second random number, a datum, a first key, and a second key, comprising:
dividing, by the parallel processing system, the image into two groups each group comprising a number of bits of the image equal to the bit width; for each group, performing, by the parallel processing system, a hash comprising: setting a new value of the datum to equal the sum of the value expressed in binary of the group and the current value of the datum multiplied by the first random number and summed with the second random number; setting a new value of the first key to equal the current value of the first key modified by the datum; and setting a new value of the second key to equal the current value of the second key modified by the datum; and after performing the hash, storing, by the parallel processing system, a big key comprising the first key and the second key in a computer memory.