Using Memcahed as real-time database in the SPARC Control System. G. Di Pirro,, E. Pace, INFN LNF, Italy

Transcription

1 Using Memcahed as real-time database in the SPARC Control System G. Di Pirro,, E. Pace, INFN LNF, Italy

2 The Frascati Laboratory DAFNE electron positron collider SPARC_LAB Free Electron Laser 2

3 The SPARC_LAB Facility SPARC_LAB is a facility based on the unique combination of high brightness electron beams, from the SPARC photo-injector, with high intensity ultra-short laser pulses, from FLAME. It will allow the investigation of all the different configurations of plasma acceleration and the development of a wide spectrum inter-disciplinary leading-edge research activity with advanced radiation sources, e.g. x-ray and THz radiation.

4 SPARC Photoinjector Diagnostic and Matching 170 MeV S-band linac 12 m Velocity Bunching Long Solenoids S-band Gun 44 th LNF SC Meeting, June 4 th, 2012 PCaPAC 2012, VECC, Kolcata, India 4

5 SPARC Photoinjector C_Band driver Velocity Bunching THz Radiation LWFA_ext THz Radiation LASER COMB Thomson PWFA DWFA FEL 44 th LNF SC Meeting, June 4 th, 2012 FEL Single Spike PCaPAC 2012, VECC, Kolcata, India 5

6 FLAME: a 300 TW Ti:Sa Laser 44 th LNF SC Meeting, June 4 th, 2012 PCaPAC 2012, VECC, Kolcata, India 6

7 The SPARC_LAB Layout Interaction chamber Plasma capillary 300 TW, < 25 fs Ti:Sa laser Thomson scattering beamline Plasma Acceleration beamline Test bench beamline for THz, EOS, advanced BPMs Undulator beamline THz beamline 44 th LNF SC Meeting, June 4 th, 2012 PCaPAC 2012, VECC, Kolcata, India 7

8 New SPARC Layout RF Modulator 3 Vacuum pump 38 Vacuometer 14 Progammble Delay 6 Magnet PS 100 Flags 30 Camera 40 Beam Position Monitor 26 Beam Current Monitor 4 8

9 CONTROL SYSTEM Operating system download Data storage Data base... Electronic logbook Web information Automatic acquisition... First level server service gigabit switch SECOND LEVEL MAGNET VACUUM DIAGNOSTI C.. THIRD LEVEL 9

10 acquires any commands from a console or from another computer puts them in a queue for execution. Sends the clusters of the elements under control at the request of the higher level Initializes all the variables for data communication and acquires information about the elements under controlled and perform any hardware initialization execute the command if present in the command queue. The second operation is the control operation. automatically writes a SQL database (PostgreSQL) of the parameters considered most significant. Saving can be done either periodically or upon significant change 10

11 HISTORY DATA COMMAND COMMAND INIT DATA History DATA Live DATA Live DATA 11

12 The whole control system was developed using LabView The control system (hardware & software) is completely defined, tested and used. All element of the machine are under control BUT Bad performance on the console window when one front-end process is stopped Slow performance when multiple interconnection 12

13 Cloud 13

14 HISTORY DATA Live DATA History DATA INIT DATA 14

15 !CHAOS L. Catani FRID01 Introducing the!chaos Control Systems Framework 15

16 Test #3.1 n x writing CU 20 x reading clients 8 core RAM 16GB writing every... (msec) #CU (Write) #clients (Read) #servers #processes/ server ? ? CPU load (%)

17 Test #3.2 8 core RAM 16GB x reading clients writing every... (msec) #CU (Write) #clients (Read) #servers #processes/ server (1 per core) (1 per core) (1 per core) 0 CPU load (%)

18 Test #4 20 x Hz 91,2 MBytes/sec! 8 core RAM 16GB 2 x reading clients s4_hardware1_w20_m20_buff100000_rd10 s4_hardware1_w20_m20_buff100000_rd12

19 Measured transfer time between front+end CU and a Client application via DOC for a different number of Concurrent clients reading the same key/value being Continuously updated by the CU. 19

20 Memcahed Open source

21 What is it Key/value store Store everything in RAM Forgetting data is a feature No persistent storage 21

22 What isn t it Database HTTP accelerator 22

23 Architecture Divided into two parts: server client Important: "intelligence" split between client and server 23

24 Server Stores the key / value pairs Clear stored data when: Is reached the deadline set by the user Runs out of memory available Not 'aware of the other server: Do not talk to them There isn t synchronization There are no messages in broadcast Don t know what is stored. 24

25 Client Available for the main programming languages Has a list of all servers Chooses each time the server on which to store data Know what to do when a server is not reach Takes care of serializing the values to be stored Know how to retrieve data 25

26 Labview implementation 26

27 Exist C library But Simple TCP/IP comunication Packet Structure 24 bytes HEADER Required Sizes are defined in the header EXTRA FIELD (Command Specific) KEY VALUE As needed 27

28 Packet Structure HEADER Two types of headers: Request Header Response Header 28

29 The Request Header MAGIC Opcode (1 byte) (1 byte) Extra Length Data Type (1 byte) (1 byte) Total Body Length (4 bytes) Opaque (4 bytes) CAS (Compare and Swap) (8 bytes) Key Length (2 bytes) Reserved (2 bytes) MAGIC 0x80 = Request Packet 29

30 The Response Header MAGIC Opcode (1 byte) (1 byte) Extra Length Data Type (1 byte) (1 byte) Total Body Length (4 bytes) Opaque (4 bytes) CAS (Compare and Swap) (8 bytes) Key Length (2 bytes) Status (2 bytes) MAGIC 0x81 = Request Packet 30

31 OPCODE Represents the Command Type 0x00 => Get 0x01 => Set 0x02 => Add 0x03 => Replace 0x04 => Delete 0x05 => Increment 0x06 => Decrement 0x07 => Quit x08 => Flush 0x09 => GetQ 0x0A => No-op 0x0B => Version 0x0C => GetK 0x0D => GetKQ 0x0E => Append 0x0F => Prepend 0x11 => Stats 31

32 Write Data 32

33 Read data 33

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35 Removed from Front-end cpu 35

36 Object abstraction MG1Sta.ctl static variables (parameters) MG1HCISta.ctl recordclass maxcmdexetime#0 0 elemname maxcmdexetime#1 maxcmdexetime#2 maxcmdexetime#3 interpolcoeff elemtype 0 polarityswitch dynamic variables MG1Dyn.ctl elemname sysflags status 0 consolename 0 errormask cmdexestarttime maxcmdexetime cmdexecution 0 online bypass remote busy readoutarray triggerarmed 0 readoutname slope offset min max sensitivity errorrange rampon currentpresetting statussetting 0 polaritysetting 0 currentsetting slewratesetting cyclemode 0 outputpolarity 0 settingarray outputcurr KEY definition <element name>_dyn <element name>_sta <element name>_dat 0 settingname slope offset min max precision MG1ExtraSta serialchid 0 slaveaddress 0 E642PgmTable slewratereadout outputvolt faults

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38 Hardware server CPU RAM Ethernet Intel Xeon 3 GHz 1 Gbyte 1 Gbit Image statistic Image 640x bit 40 ms sample variance 8 ms ( byte) Image 640x480 8 bit 23 mssample variance 8 ms ( byte) Don t see variation from 1 until 4 consoles in acquisition 38

39 Conclusion The use of cached data has demonstrated both in performance and in simplicity of realization. Now the control system is completely past to use Memcached as RTDB. 39