imrcpan/erofs-linux
1
0 Fork 0
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git synced 2026-11-12 04:22:27 +01:00
Code Issues Packages Projects Releases Wiki Activity
948,892 Commits 5 Branches 1,034 Tags
94dea151bf3651c01acb12a38ca75ba9d26ea4da
Commit Graph
2 Commits
Author SHA1 Message Date
Andrei Vagin 0898a16a36 lib/vdso: Add unlikely() hint into vdso_read_begin() 
Place the branch with no concurrent write before the contended case.

Performance numbers for Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz
(more clock_gettime() cycles - the better):
        | before    | after
-----------------------------------
        | 150252214 | 153242367
        | 150301112 | 153324800
        | 150392773 | 153125401
        | 150373957 | 153399355
        | 150303157 | 153489417
        | 150365237 | 153494270
-----------------------------------
avg     | 150331408 | 153345935
diff %  | 2	    | 0
-----------------------------------
stdev % | 0.3	    | 0.1

Co-developed-by: Dmitry Safonov <[email protected]>
Signed-off-by: Andrei Vagin <[email protected]>
Signed-off-by: Dmitry Safonov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Vincenzo Frascino <[email protected]>
Reviewed-by: Vincenzo Frascino <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
 2020-01-14 12:20:47 +01:00
Vincenzo Frascino 00b26474c2 lib/vdso: Provide generic VDSO implementation 
In the last few years the kernel gained quite some architecture specific
vdso implementations which contain very similar code.

Introduce a generic VDSO implementation of gettimeofday() which will be
shareable between architectures once they are converted over.

The implementation is based on the current x86 VDSO code.

[ tglx: Massaged changelog and made the kernel doc tabular ]

Signed-off-by: Vincenzo Frascino <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Shijith Thotton <[email protected]>
Tested-by: Andre Przywara <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Russell King <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Cc: Mark Salyzyn <[email protected]>
Cc: Peter Collingbourne <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Dmitry Safonov <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Huw Davies <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
 2019-06-22 21:21:05 +02:00