summaryrefslogtreecommitdiffstats
path: root/vendor/golang.org/x/sys/unix/affinity_linux.go
diff options
context:
space:
mode:
authorGlenn Vriesman <glenn.vriesman@gmail.com>2019-11-10 13:16:17 +0100
committerJesse Duffield <jessedduffield@gmail.com>2019-11-10 23:23:20 +1100
commit3f7e107d09a675b28783584d3643ee112206d905 (patch)
treed8622a53c93e2d89e9e3ddf1b0a647a28b6fa752 /vendor/golang.org/x/sys/unix/affinity_linux.go
parent22c0d79e2dbb8a6792664e1a56fa91f28592bbc0 (diff)
Vendor: Updated dependenciesv0.10.2
* Updated go.mod * Updated go.sum * Updated vendor packages Signed-off-by: Glenn Vriesman <glenn.vriesman@gmail.com>
Diffstat (limited to 'vendor/golang.org/x/sys/unix/affinity_linux.go')
-rw-r--r--vendor/golang.org/x/sys/unix/affinity_linux.go42
1 files changed, 2 insertions, 40 deletions
diff --git a/vendor/golang.org/x/sys/unix/affinity_linux.go b/vendor/golang.org/x/sys/unix/affinity_linux.go
index 72afe3338..6e5c81acd 100644
--- a/vendor/golang.org/x/sys/unix/affinity_linux.go
+++ b/vendor/golang.org/x/sys/unix/affinity_linux.go
@@ -7,6 +7,7 @@
package unix
import (
+ "math/bits"
"unsafe"
)
@@ -79,46 +80,7 @@ func (s *CPUSet) IsSet(cpu int) bool {
func (s *CPUSet) Count() int {
c := 0
for _, b := range s {
- c += onesCount64(uint64(b))
+ c += bits.OnesCount64(uint64(b))
}
return c
}
-
-// onesCount64 is a copy of Go 1.9's math/bits.OnesCount64.
-// Once this package can require Go 1.9, we can delete this
-// and update the caller to use bits.OnesCount64.
-func onesCount64(x uint64) int {
- const m0 = 0x5555555555555555 // 01010101 ...
- const m1 = 0x3333333333333333 // 00110011 ...
- const m2 = 0x0f0f0f0f0f0f0f0f // 00001111 ...
- const m3 = 0x00ff00ff00ff00ff // etc.
- const m4 = 0x0000ffff0000ffff
-
- // Implementation: Parallel summing of adjacent bits.
- // See "Hacker's Delight", Chap. 5: Counting Bits.
- // The following pattern shows the general approach:
- //
- // x = x>>1&(m0&m) + x&(m0&m)
- // x = x>>2&(m1&m) + x&(m1&m)
- // x = x>>4&(m2&m) + x&(m2&m)
- // x = x>>8&(m3&m) + x&(m3&m)
- // x = x>>16&(m4&m) + x&(m4&m)
- // x = x>>32&(m5&m) + x&(m5&m)
- // return int(x)
- //
- // Masking (& operations) can be left away when there's no
- // danger that a field's sum will carry over into the next
- // field: Since the result cannot be > 64, 8 bits is enough
- // and we can ignore the masks for the shifts by 8 and up.
- // Per "Hacker's Delight", the first line can be simplified
- // more, but it saves at best one instruction, so we leave
- // it alone for clarity.
- const m = 1<<64 - 1
- x = x>>1&(m0&m) + x&(m0&m)
- x = x>>2&(m1&m) + x&(m1&m)
- x = (x>>4 + x) & (m2 & m)
- x += x >> 8
- x += x >> 16
- x += x >> 32
- return int(x) & (1<<7 - 1)
-}