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| 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/vdso32/clock_gettime.S | |
| parent | 369e8c355383143964290b6a706eb6639ae3588c (diff) | |
| download | talos-obmc-linux-070b7be633dc33c0899e8c934b4d5fad046b06e8.tar.gz talos-obmc-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/vdso32/clock_gettime.S')
| -rw-r--r-- | arch/s390/kernel/vdso32/clock_gettime.S | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/s390/kernel/vdso32/clock_gettime.S b/arch/s390/kernel/vdso32/clock_gettime.S index 7cf18f8d4cb4..4e20a9365bb7 100644 --- a/arch/s390/kernel/vdso32/clock_gettime.S +++ b/arch/s390/kernel/vdso32/clock_gettime.S @@ -30,8 +30,8 @@ __kernel_clock_gettime: 1: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */ tml %r4,0x0001 /* pending update ? loop */ jnz 1b - stck 24(%r15) /* Store TOD clock */ - lm %r0,%r1,24(%r15) + stcke 24(%r15) /* Store TOD clock */ + lm %r0,%r1,25(%r15) s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ sl %r1,__VDSO_XTIME_STAMP+4(%r5) brc 3,2f @@ -72,8 +72,8 @@ __kernel_clock_gettime: 11: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */ tml %r4,0x0001 /* pending update ? loop */ jnz 11b - stck 24(%r15) /* Store TOD clock */ - lm %r0,%r1,24(%r15) + stcke 24(%r15) /* Store TOD clock */ + lm %r0,%r1,25(%r15) s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ sl %r1,__VDSO_XTIME_STAMP+4(%r5) brc 3,12f |
