1. ORGANIZING AND ADMINISTERING OF VOLUNTEER DISTRIBUTED COMPUTING PROJECT SAT@HOME Oleg Zaikin, Nikolay Khrapov Institute for System Dynamics and Control Theory SB RAS, Irkutsk, Russia Institute for Systems Analysis RAS, Moskow, Russia

2. Volunteer computing project SAT@home Started on 29 September 2011 Goal - solve hard large-scale problems that can be effectively reduced to SAT. Applicability: cryptography search for combinatorial structures bioinformatics App versions: win_x86, linux_x86, linux_x64

3. General scheme While finding parameters of decomposition we take into account peculiarities of the original problems CNF encoding of the original problem is decomposed into a set of independent CNFs

4. Experiments First experiment started on 21 December 2011 and finished on 7 May 2012. 10 problems of cryptanalysis of the generator A5/1 (used in GSM) were solved in using SAT approach. These problems can not be solved by Rainbow method (most popular for A5/1). Second experiment started on 25 May 2012. The goal is to find a triple of mutual orthogonal diagonal Latin squares of order 10

5. MTA SZTAKI tools in SAT@home Implemented using SZTAKI Desktop Grid package (modified BOINC) + DC-API. SZTAKI Desktop Grid package Easier (than standard BOINC) to deploy No support for new versions of BOINC DC-API Easier (than standard BOINC API) to implement distributed applications No libraries for building client applications for Mac OS and 64-bit Windows

6. New server TODO: Move to standard BOINC server package and API. 1.Rewrite distributed application using BOINC API 2.Deploy new BOINC server 3.Move content of site and DB from old server 4.Start new server (with same URL)

7. Server workability In January 2012 due to the substantial increase of workunits DB (MySQL) switched to read-only mode. After about 12 hours it was manually switched to standard mode. As a result server could not cope with long list of queries (generation of new tasks, processing results).

8. Server status Normal situation (18 July 2012) In the middle of January 2012 Transitioner backlog value was 26 hours

9. Increasing of server performance Additional resources were added to VM Database settings were changed using mysqltuner.pl Logging mode of daemons was changed (I/O was a bottleneck) Old workunits were removed from DB TODO: move old data (1 month old) to another DB which can be huge and slow. Additional validator (for checking correctness of results) was launched.

10. Monitoring toolkit A toolkit for collecting statistics and monitoring of the Grid was developed. It shows: dynamics of the project as graphs; acceleration of the grid performance; statistics about hosts and users (platforms, countries, etc). Google Web Toolkit, Perl and php were used.

11. Monitoring toolkit

12. SAT@home resources 18 July 2012 All hosts: 7586 Windows: 6285 (82 %) Linux: 1179 Mac: 74 All CPU cores 30167 Users 2349 (from 80 countries) Active users 1062 Active means “returned a result in the last month”.

13. SAT@home performance Current: 2.3 TFLOPs Peak: 4.3 TFLOPs Last month dynamics

14. TODO list New server with “pure” BOINC Version of application for Mac OS Connect new clusters to SAT@home Improve algorithms for solving our SAT problems GPU application (may be)

15. BOINC http://boinc.berkeley.edu SAT@home http://sat.isa.ru Thank you for your attention! Join the volunteer computing!