Add check for sched_yield in librt #31
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In Solaris, sched_yield lives in librt, rather than libc. This patch adds a check which will link in librt if necessary.
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This looks perfect. Small/compact/goes from "not work" to "work". |
Contributor
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Thanks! |
xfxyjwf
added a commit
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this pull request
Sep 22, 2014
Add check for sched_yield in librt
TeBoring
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to TeBoring/protobuf
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Jan 19, 2019
Moved DynASM to third_party to comply with Google policy.
copybara-service bot
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Nov 28, 2024
Loop body before:
```
.LBB0_2:
add w8, w12, #1
cmp w8, w11
b.gt .LBB0_6 // Predictable branch, ends the loop
.LBB0_3:
add w12, w8, w11
add w12, w12, w12, lsr #31
asr w12, w12, #1
smaddl x0, w12, w10, x9
ldr w13, [x0]
cmp w13, w1
b.lo .LBB0_2 // Unpredictable branch here! Will be hit 50/50 in prod
b.ls .LBB0_7 // Predictable branch - ends the loop
sub w11, w12, #1
cmp w8, w11
b.le .LBB0_3 // Predictable branch - continues the loop
```
Loop body after:
```
.LBB7_1:
cmp w9, w11
b.hi .LBB7_4 // Predictable branch - ends the loop
add w12, w9, w11
lsr w12, w12, #1
umaddl x0, w12, w8, x10
sub w14, w12, #1
ldr w13, [x0]
cmp w13, w1
csel w11, w14, w11, hs
csinc w9, w9, w12, hs
b.ne .LBB7_1 // Predictable branch - continues the loop
```
PiperOrigin-RevId: 700864625
copybara-service bot
pushed a commit
that referenced
this pull request
Dec 4, 2024
On a Cortex-A55 this resulted in a 28.30% reduction in CPU and wall time for the binary search path.
Loop body before:
```
.LBB0_2:
add w8, w12, #1
cmp w8, w11
b.gt .LBB0_6 // Predictable branch, ends the loop
.LBB0_3:
add w12, w8, w11
add w12, w12, w12, lsr #31
asr w12, w12, #1
smaddl x0, w12, w10, x9
ldr w13, [x0]
cmp w13, w1
b.lo .LBB0_2 // Unpredictable branch here! Will be hit 50/50 in prod
b.ls .LBB0_7 // Predictable branch - ends the loop
sub w11, w12, #1
cmp w8, w11
b.le .LBB0_3 // Predictable branch - continues the loop
```
Loop body after:
```
.LBB7_1:
cmp w9, w11
b.hi .LBB7_4 // Predictable branch - ends the loop
add w12, w9, w11
lsr w12, w12, #1
umaddl x0, w12, w8, x10
sub w14, w12, #1
ldr w13, [x0]
cmp w13, w1
csel w11, w14, w11, hs
csinc w9, w9, w12, hs
b.ne .LBB7_1 // Predictable branch - continues the loop
```
PiperOrigin-RevId: 700864625
copybara-service bot
pushed a commit
that referenced
this pull request
Dec 4, 2024
On a Cortex-A55 this resulted in a 28.30% reduction in CPU and wall time for the binary search path.
Loop body before:
```
.LBB0_2:
add w8, w12, #1
cmp w8, w11
b.gt .LBB0_6 // Predictable branch, ends the loop
.LBB0_3:
add w12, w8, w11
add w12, w12, w12, lsr #31
asr w12, w12, #1
smaddl x0, w12, w10, x9
ldr w13, [x0]
cmp w13, w1
b.lo .LBB0_2 // Unpredictable branch here! Will be hit 50/50 in prod
b.ls .LBB0_7 // Predictable branch - ends the loop
sub w11, w12, #1
cmp w8, w11
b.le .LBB0_3 // Predictable branch - continues the loop
```
Loop body after:
```
.LBB7_1:
cmp w9, w11
b.hi .LBB7_4 // Predictable branch - ends the loop
add w12, w9, w11
lsr w12, w12, #1
umaddl x0, w12, w8, x10
sub w14, w12, #1
ldr w13, [x0]
cmp w13, w1
csel w11, w14, w11, hs
csinc w9, w9, w12, hs
b.ne .LBB7_1 // Predictable branch - continues the loop
```
PiperOrigin-RevId: 700864625
copybara-service bot
pushed a commit
that referenced
this pull request
Dec 4, 2024
On a Cortex-A55 this resulted in a 28.30% reduction in CPU and wall time for the binary search path.
Loop body before:
```
.LBB0_2:
add w8, w12, #1
cmp w8, w11
b.gt .LBB0_6 // Predictable branch, ends the loop
.LBB0_3:
add w12, w8, w11
add w12, w12, w12, lsr #31
asr w12, w12, #1
smaddl x0, w12, w10, x9
ldr w13, [x0]
cmp w13, w1
b.lo .LBB0_2 // Unpredictable branch here! Will be hit 50/50 in prod
b.ls .LBB0_7 // Predictable branch - ends the loop
sub w11, w12, #1
cmp w8, w11
b.le .LBB0_3 // Predictable branch - continues the loop
```
Loop body after:
```
.LBB7_1:
cmp w9, w11
b.hi .LBB7_4 // Predictable branch - ends the loop
add w12, w9, w11
lsr w12, w12, #1
umaddl x0, w12, w8, x10
sub w14, w12, #1
ldr w13, [x0]
cmp w13, w1
csel w11, w14, w11, hs
csinc w9, w9, w12, hs
b.ne .LBB7_1 // Predictable branch - continues the loop
```
PiperOrigin-RevId: 700864625
copybara-service bot
pushed a commit
that referenced
this pull request
Dec 4, 2024
On a Cortex-A55 this resulted in a 28.30% reduction in CPU and wall time for the binary search path.
Loop body before:
```
.LBB0_2:
add w8, w12, #1
cmp w8, w11
b.gt .LBB0_6 // Predictable branch, ends the loop
.LBB0_3:
add w12, w8, w11
add w12, w12, w12, lsr #31
asr w12, w12, #1
smaddl x0, w12, w10, x9
ldr w13, [x0]
cmp w13, w1
b.lo .LBB0_2 // Unpredictable branch here! Will be hit 50/50 in prod
b.ls .LBB0_7 // Predictable branch - ends the loop
sub w11, w12, #1
cmp w8, w11
b.le .LBB0_3 // Predictable branch - continues the loop
```
Loop body after:
```
.LBB7_1:
cmp w9, w11
b.hi .LBB7_4 // Predictable branch - ends the loop
add w12, w9, w11
lsr w12, w12, #1
umaddl x0, w12, w8, x10
sub w14, w12, #1
ldr w13, [x0]
cmp w13, w1
csel w11, w14, w11, hs
csinc w9, w9, w12, hs
b.ne .LBB7_1 // Predictable branch - continues the loop
```
PiperOrigin-RevId: 700864625
copybara-service bot
pushed a commit
that referenced
this pull request
Dec 5, 2024
On a Cortex-A55 this resulted in a 28.30% reduction in CPU and wall time for the binary search path.
Loop body before:
```
.LBB0_2:
add w8, w12, #1
cmp w8, w11
b.gt .LBB0_6 // Predictable branch, ends the loop
.LBB0_3:
add w12, w8, w11
add w12, w12, w12, lsr #31
asr w12, w12, #1
smaddl x0, w12, w10, x9
ldr w13, [x0]
cmp w13, w1
b.lo .LBB0_2 // Unpredictable branch here! Will be hit 50/50 in prod
b.ls .LBB0_7 // Predictable branch - ends the loop
sub w11, w12, #1
cmp w8, w11
b.le .LBB0_3 // Predictable branch - continues the loop
```
Loop body after:
```
.LBB7_1:
cmp w9, w11
b.hi .LBB7_4 // Predictable branch - ends the loop
add w12, w9, w11
lsr w12, w12, #1
umaddl x0, w12, w8, x10
sub w14, w12, #1
ldr w13, [x0]
cmp w13, w1
csel w11, w14, w11, hs
csinc w9, w9, w12, hs
b.ne .LBB7_1 // Predictable branch - continues the loop
```
PiperOrigin-RevId: 703213921
copybara-service bot
pushed a commit
that referenced
this pull request
Dec 5, 2024
On a Cortex-A55 this resulted in a 28.30% reduction in CPU and wall time for the binary search path.
Loop body before:
```
.LBB0_2:
add w8, w12, #1
cmp w8, w11
b.gt .LBB0_6 // Predictable branch, ends the loop
.LBB0_3:
add w12, w8, w11
add w12, w12, w12, lsr #31
asr w12, w12, #1
smaddl x0, w12, w10, x9
ldr w13, [x0]
cmp w13, w1
b.lo .LBB0_2 // Unpredictable branch here! Will be hit 50/50 in prod
b.ls .LBB0_7 // Predictable branch - ends the loop
sub w11, w12, #1
cmp w8, w11
b.le .LBB0_3 // Predictable branch - continues the loop
```
Loop body after:
```
.LBB7_1:
cmp w9, w11
b.hi .LBB7_4 // Predictable branch - ends the loop
add w12, w9, w11
lsr w12, w12, #1
umaddl x0, w12, w8, x10
sub w14, w12, #1
ldr w13, [x0]
cmp w13, w1
csel w11, w14, w11, hs
csinc w9, w9, w12, hs
b.ne .LBB7_1 // Predictable branch - continues the loop
```
PiperOrigin-RevId: 703214356
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In Solaris, sched_yield lives in librt, rather than libc. This patch adds a
check which will link in librt if necessary.