LOOKUP MACHINE characterization Chanit Giat Rachel Stahl Instructor: Artyom Borzin הטכניון - מכון טכנולוגי לישראל המעבדה למערכות ספרתיות מהירות הפקולטה להנדסת חשמל

Data Flow Through The Machine Bit Map Table CAT, AT המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory

Commands Init Init Search Search Set attributes Set attributes Delete Delete Count free Count free (age) (age) המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory

Local Bus Interface Data Stream Controller Output FIFO 4x32 Input FIFO 256x37 Valid Byte Filter Register File המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory

1 st Improvement: 2 Input FIFO’s Adding a second input FIFO: Adding a second input FIFO: Better handling the load of the user’s requests. Better handling the load of the user’s requests. It enables scheduling of different types of commands (i.e. set attributes vs. search), and executing them OOO. It enables scheduling of different types of commands (i.e. set attributes vs. search), and executing them OOO. It is a 1 st step on the way to a 2 nd possible improvement: adding a 2 nd decoder. It is a 1 st step on the way to a 2 nd possible improvement: adding a 2 nd decoder. Problem: accesses to the CRC unit and the DBM should be monitored and scheduled. Problem: accesses to the CRC unit and the DBM should be monitored and scheduled. המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory

3 rd Improvement: Pipelining Decoded Instructions Present situation: the decoder doesn’t begin to decode a new instruction until the pervious one is done executing in the DBM. Present situation: the decoder doesn’t begin to decode a new instruction until the pervious one is done executing in the DBM. Local Bus Interface DecoderDBM Local Bus Interface DecoderDBM FIFO המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory

Data Base Manager המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory

Search command flow Calculate 64bit CRC value for the received data Query CAT for entry with [Site#, CRC] Found Insert new record to CAT and AT Successf ul Return PATH and Status Return ErrorReturn PATH and Status No Yes Find the next empty place in CAT המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory

4 th improvement: Parallel access to the Bit Map Table and to the CAT. Parallel access to the Bit Map Table and to the CAT. Calculate 64bit CRC value for the received data Query CAT for entry with [Site#, CRC] Found Insert new record to CAT and AT Successf ul Return PATH and Status Return ErrorReturn PATH and Status No Yes Find the next empty place in CAT המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory

Reliability Issues Currently we use only the 64 bits of the CRC code as a unique representation of the data. In order to lower even more the chance of collision (two strings having the same code), we should use 96 bits of the site field and the CRC. Currently we use only the 64 bits of the CRC code as a unique representation of the data. In order to lower even more the chance of collision (two strings having the same code), we should use 96 bits of the site field and the CRC. The ‘delete’ and ‘set attributes’ commands do not check if the appropriate entry is full. We will to add a reference to the BMT to check if the entry is valid. The ‘delete’ and ‘set attributes’ commands do not check if the appropriate entry is full. We will to add a reference to the BMT to check if the entry is valid. המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory

Schedule (est.) - mid May : study the project (including code). - mid May : study the project (including code). mid May: mid semester presentation, will include: mid May: mid semester presentation, will include: The improvements we chose to look into and try to implement. The improvements we chose to look into and try to implement. The changes needed to be done, at least architecture- wise. The changes needed to be done, at least architecture- wise. May – mid July: implementation. May – mid July: implementation. End of July: final presentation. End of July: final presentation. המעבדה למערכות ספרתיות מהירות High speed digital systems laboratory