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Use cgo to get systems clock ticks for metrics Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

Michael Crosby authored on 2014/04/22 02:26:03
Showing 4 changed files

pkg/cgroups/fs/cpuacct.go index 8c123b7..4ea2b1f 100644
pkg/system/sysconfig.go index 0000000..dcbe6c9
pkg/system/sysconfig_nocgo.go index 0000000..7ca3488
pkg/system/unsupported.go index c52a1e5..4ae2a48 100644

@@ -14,7 +14,10 @@ import (
 	"github.com/dotcloud/docker/pkg/system"
 )
 
-var cpuCount = float64(runtime.NumCPU())
+var (
+	cpuCount   = float64(runtime.NumCPU())
+	clockTicks = float64(system.GetClockTicks())
+)
 
 type cpuacctGroup struct {
 }
@@ -58,7 +61,7 @@ func (s *cpuacctGroup) Stats(d *data) (map[string]float64, error) {
 		deltaSystem = lastSystem - startSystem
 	)
 	if deltaSystem > 0.0 {
-		percentage = ((deltaProc / deltaSystem) * 100.0) * cpuCount
+		percentage = ((deltaProc / deltaSystem) * clockTicks) * cpuCount
 	}
 	// NOTE: a percentage over 100% is valid for POSIX because that means the
 	// processes is using multiple cores

pkg/system/sysconfig.go

History View file @ 004cf55

                     new file mode 100644
@@ -0,0 +1,13 @@
                     +// +build linux,cgo
+                    +
                     +package system
+                    +
                     +/*
                     +#include <unistd.h>
                     +int get_hz(void) { return sysconf(_SC_CLK_TCK); }
                     +*/
                     +import "C"
+                    +
                     +func GetClockTicks() int {
                     +	return int(C.get_hz())
                     +}

pkg/system/sysconfig_nocgo.go

History View file @ 004cf55

                     new file mode 100644
@@ -0,0 +1,9 @@
                     +// +build linux,!cgo
+                    +
                     +package system
+                    +
                     +func GetClockTicks() int {
                     +	// when we cannot call out to C to get the sysconf it is fairly safe to
                     +	// just return 100
                     +	return 100
                     +}

pkg/system/unsupported.go

History View file @ 004cf55

@@ -17,3 +17,9 @@ func UsetCloseOnExec(fd uintptr) error {
                      func Gettid() int {
                      	return 0
+                     }
+                    +
                     +func GetClockTicks() int {
                     +	// when we cannot call out to C to get the sysconf it is fairly safe to
                     +	// just return 100
                     +	return 100
                     +}

...	...	@@ -14,7 +14,10 @@ import (
14	14	"github.com/dotcloud/docker/pkg/system"
15	15	)
16	16
17		-var cpuCount = float64(runtime.NumCPU())
	17	+var (
	18	+ cpuCount = float64(runtime.NumCPU())
	19	+ clockTicks = float64(system.GetClockTicks())
	20	+)
18	21
19	22	type cpuacctGroup struct {
20	23	}
...	...	@@ -58,7 +61,7 @@ func (s cpuacctGroup) Stats(d data) (map[string]float64, error) {
58	58	deltaSystem = lastSystem - startSystem
59	59	)
60	60	if deltaSystem > 0.0 {
61		- percentage = ((deltaProc / deltaSystem) * 100.0) * cpuCount
	61	+ percentage = ((deltaProc / deltaSystem) * clockTicks) * cpuCount
62	62	}
63	63	// NOTE: a percentage over 100% is valid for POSIX because that means the
64	64	// processes is using multiple cores