README
¶
massif
massif is a library for working with logs produced by massif, a tool contained in the
Valgrind suite. This library can make it easy to do things like write an
automated test to verify peak heap usage in a binary. The linked godoc contains
usage examples.
Documentation
¶
Overview ¶
Package massif implements a basic (likely incomplete parser) for heap profiles generated by the Massif tool. Massif is part of the Valgrind suite of tools, more information can be found at: https://valgrind.org/docs/manual/ms-manual.html
See the examples for basic usage.
Example ¶
package main
import (
"encoding/json"
"fmt"
"log"
"os"
"github.com/joshkunz/massif"
)
func main() {
// Load the example massif file off disk.
f, err := os.Open("testdata/example.massif")
if err != nil {
log.Fatalf("failed to open testdata/example.massif: %v", err)
}
defer f.Close()
parsed, err := massif.Parse(f)
if err != nil {
log.Fatalf("failed to parse testdata/example.massif: %v", err)
}
// Convert the Massif struct into JSON for display purposes only. This is
// not required.
display, err := json.MarshalIndent(parsed, "", " ")
if err != nil {
log.Fatalf("failed to marshal Massif for display: %v", err)
}
fmt.Print(string(display))
}
Output: { "Description": "--massif-out-file=./example.massif", "Binary": "example_binary", "Args": [ "--option-one", "--option-two", "--flag=value" ], "TimeUnit": "i", "Snapshots": [ { "Index": 0, "Time": "0", "MemoryHeap": 0, "MemoryHeapExtra": 0, "MemoryStack": 0, "HeapTree": "" }, { "Index": 1, "Time": "103242501", "MemoryHeap": 8988696, "MemoryHeapExtra": 713576, "MemoryStack": 0, "HeapTree": "Note: This heap is snipped.\nn6: 1123587 (heap allocation functions) malloc/new/new[], --alloc-fns, etc.\n n0: 12558 in 28 places, all below massif's threshold (1.00%)" }, { "Index": 2, "Time": "161677632", "MemoryHeap": 12931384, "MemoryHeapExtra": 1124552, "MemoryStack": 0, "HeapTree": "Note: This heap is snipped.\nn6: 1616423 (heap allocation functions) malloc/new/new[], --alloc-fns, etc.\n n0: 13839 in 28 places, all below massif's threshold (1.00%)" }, { "Index": 3, "Time": "273947848", "MemoryHeap": 22066184, "MemoryHeapExtra": 1915064, "MemoryStack": 0, "HeapTree": "" } ] }
Example (PeakUsage) ¶
ExamplePeakUsage prints the peak memory usage found in the example massif run.
package main
import (
"fmt"
"log"
"os"
"github.com/joshkunz/massif"
)
func main() {
// Load the example massif file off disk.
f, err := os.Open("testdata/example.massif")
if err != nil {
log.Fatalf("failed to open testdata/example.massif: %v", err)
}
defer f.Close()
parsed, err := massif.Parse(f)
if err != nil {
log.Fatalf("failed to parse testdata/example.massif: %v", err)
}
var max *massif.Snapshot
for _, snap := range parsed.Snapshots {
if max == nil || snap.MemoryHeap > max.MemoryHeap {
max = &snap
}
}
fmt.Printf("Max memory usage of %.2f MiB in snapshot %d at time %s%s",
max.MemoryHeap.Mebibytes(), max.Index, max.Time, parsed.TimeUnit)
}
Output: Max memory usage of 2.63 MiB in snapshot 3 at time 273947848i
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Massif ¶
type Massif struct {
Description string
Binary string
Args []string
TimeUnit string
Snapshots []Snapshot
}
Massif represents a parsed Massif output file. The fields in this struct correspond to the fields in the Massif file "header". Binary is the command that was run under Massif, and Args are any flags that were provided to the binary during analysis.
type Snapshot ¶
type Snapshot struct {
// Index is index of this snapshot in the Massif output file.
Index int
// Time is the raw repesentation of the time this snapshot was taken saved
// in the Massif output file. The units of this file depend on
// `Massif.TimeUnit`.
Time string
MemoryHeap unit.Datasize
MemoryHeapExtra unit.Datasize
MemoryStack unit.Datasize
// HeapTree is the raw representation of the "heap tree" included in the
// output file.
HeapTree string
}
Snapshot is the type of a "heap snapshot". Massif files are basically a sequence of these taken over the life of the program being analyzed.
Source Files