diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-08-29 12:44:40 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-09-09 08:53:27 +0200 |
| commit | 070b7be633dc33c0899e8c934b4d5fad046b06e8 (patch) | |
| tree | 4aa06300e711c8079754745e34852ac12c4dbfbf /arch/s390/kernel/vdso64/gettimeofday.S | |
| parent | Documentation/kprobes: add s390 to list of supported architectures (diff) | |
| download | linux-070b7be633dc33c0899e8c934b4d5fad046b06e8.tar.xz linux-070b7be633dc33c0899e8c934b4d5fad046b06e8.zip | |
s390/vdso: replace stck with stcke
If gettimeofday / clock_gettime are called multiple times in a row
the STCK instruction will stall until a difference in the result is
visible. This unnecessarily slows down the vdso calls, use stcke
instead of stck to get rid of the stall.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/vdso64/gettimeofday.S')
| -rw-r--r-- | arch/s390/kernel/vdso64/gettimeofday.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/s390/kernel/vdso64/gettimeofday.S b/arch/s390/kernel/vdso64/gettimeofday.S index d0860d1d0ccc..7a344995a97f 100644 --- a/arch/s390/kernel/vdso64/gettimeofday.S +++ b/arch/s390/kernel/vdso64/gettimeofday.S @@ -28,8 +28,8 @@ __kernel_gettimeofday: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ tmll %r4,0x0001 /* pending update ? loop */ jnz 0b - stck 48(%r15) /* Store TOD clock */ - lg %r1,48(%r15) + stcke 48(%r15) /* Store TOD clock */ + lg %r1,49(%r15) sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */ alg %r1,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */ |