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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-08-29 14:44:40 +0400 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-09-09 10:53:27 +0400 |
| commit | 070b7be633dc33c0899e8c934b4d5fad046b06e8 (patch) | |
| tree | 4aa06300e711c8079754745e34852ac12c4dbfbf /arch/s390/kernel/vdso64/clock_gettime.S | |
| parent | 369e8c355383143964290b6a706eb6639ae3588c (diff) | |
| download | linux-070b7be633dc33c0899e8c934b4d5fad046b06e8.tar.xz | |
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/clock_gettime.S')
| -rw-r--r-- | arch/s390/kernel/vdso64/clock_gettime.S | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/s390/kernel/vdso64/clock_gettime.S b/arch/s390/kernel/vdso64/clock_gettime.S index 3f34e09db5f4..4add40b78ed5 100644 --- a/arch/s390/kernel/vdso64/clock_gettime.S +++ b/arch/s390/kernel/vdso64/clock_gettime.S @@ -33,10 +33,10 @@ __kernel_clock_gettime: 0: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ tmll %r4,0x0001 /* pending update ? loop */ jnz 0b - stck 48(%r15) /* Store TOD clock */ + stcke 48(%r15) /* Store TOD clock */ lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */ lg %r0,__VDSO_WTOM_SEC(%r5) - lg %r1,48(%r15) + lg %r1,49(%r15) sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */ alg %r1,__VDSO_WTOM_NSEC(%r5) @@ -58,9 +58,9 @@ __kernel_clock_gettime: 5: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ tmll %r4,0x0001 /* pending update ? loop */ jnz 5b - stck 48(%r15) /* Store TOD clock */ + stcke 48(%r15) /* Store TOD clock */ lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */ - lg %r1,48(%r15) + 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 */ |