redonkable/alistair23-linux
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s390/vdso: replace stck with stcke

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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>
This commit is contained in:
Martin Schwidefsky 2014-08-29 12:44:40 +02:00
parent 369e8c3553
commit 070b7be633
4 changed files with 12 additions and 12 deletions
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8
arch/s390/kernel/vdso32/clock_gettime.S
View file

@ -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

4
arch/s390/kernel/vdso32/gettimeofday.S
View file

@ -29,8 +29,8 @@ __kernel_gettimeofday:
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 3,3f

8
arch/s390/kernel/vdso64/clock_gettime.S
View file

@ -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 */

4
arch/s390/kernel/vdso64/gettimeofday.S
View file

@ -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 */