The document discusses improving the cold startup performance of OpenOffice.org 3.2. It summarizes the improvements made in OO3.2 including reducing the number of libraries loaded at startup by merging libraries. It then discusses the PE file format and how merging two libraries reduces the number of files opened and amount of data read from disk. Test results showed merging 65 libraries into 10 in OO1.1 reduced the number of libraries loaded at startup from 68 to 24, improving the cold startup time.

1. Cold startup performance: squeezing more out of OpenOffice.org 3.2 Cheng Yuan Lotus Symphony Performance team, IBM

3. PE file format and dll loading

4. Merge libraries: result

5. Further discussion

8. Not rebase

13. PE file format and dll loading

14. Merge libraries: result

15. Further discussion

17. PE header (read in memory)

18. Section table (read in memory)

19. .text: code (map to memory space, pre-fetch several pages)

20. .data (map to memory space, pre-fetch several pages)

21. .idata: Imports section( IAT/INT )(read in memory)

22. .edata: Exports section( EAT/ENT ) (read in memory)

24. Read MS-DOS header/PE header/section table into memory

25. Map .text / .data to memory space, pre-fetch some pages of these 2 sectoins.

28. Read 2 times of MS-DOS header/PE header/section table into memory -> read 1 time : reduce disk seek time and IO.

29. Read 2 times of .idata/.edata section into memory -> read 1 time : reduce disk seek time, part of 2 .idata may be merged : reduce IO.

32. PE file format and dll loading

33. Merge libraries: result

34. Further discussion

35. Merged libraries list

36. Result on OO1.1/Symphony 1.x Merge count : 65 libraries => merged into 10 libraries. Libraries loaded in startup : before merge 68 => after 24 FAT32: NTFS: ThinkPad T41 P1.6G 768M Windows XP 'soffice.exe -writer' to start writer.

37. Detail implementation Merge : DLL1 + DLL2 = DLL2 1)Modify makefile of DLL1: don't generate DLL1; instead generate a static lib for it. 2)Modify d.lst of DLL1, deliver the static lib into solver. 3)Modify makefile of DLL2: make the static lib of DLL1 as a input of DLL2.. 4)Add export function name list of DLL1 into DLL2's list. 5)Modify all makefiles of modules which depend on DLL1, change the dependency from DLL1 import lib to DLL2 import lib. 6)Modify build.lst of DLL2: making DLL1 module get built before DLL2 module start build. 7)If DLL1 and DLL2 have global functions/variables which share same name, modify them. 8)If resource ID of DLL1 and DLL2 conflict, modify them. 9)If DLL1 and DLL2 are UNO component DLLs, need to modify the implementation code of UNO factory. 10) Modify scp, making DLL1 will not be installed.

39. Not have to merge the source code directories

40. Merge dlls in different modules or same module.

41. UNO libraries

42. Startup sequence

43. Logic relationship

45. PE file format and dll loading

46. Merge libraries: result

47. Further discussion

49. Free Discussion Cold startup time Time (seconds) IO size (MB) MS office XP 2.8 1.5 Merged OO1.1 12.5 10.9

50. THANKS