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https://issues.apache.org/jira/browse/BEAM-3324?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16293050#comment-16293050
]
ASF GitHub Bot commented on BEAM-3324:
--------------------------------------
kennknowles closed pull request #4256: [BEAM-3324] Cache Go runtime symbol
lookups
URL: https://github.com/apache/beam/pull/4256
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):
diff --git a/sdks/go/pkg/beam/core/runtime/symbols.go
b/sdks/go/pkg/beam/core/runtime/symbols.go
index f9c839c948b..2659f4834eb 100644
--- a/sdks/go/pkg/beam/core/runtime/symbols.go
+++ b/sdks/go/pkg/beam/core/runtime/symbols.go
@@ -17,6 +17,7 @@ package runtime
import (
"os"
+ "sync"
"github.com/apache/beam/sdks/go/pkg/beam/core/util/symtab"
)
@@ -26,6 +27,7 @@ import (
// SymbolResolution is the interface that should be implemented
// in order to override the default behavior for symbol resolution.
type SymbolResolution interface {
+ // Sym2Addr returns the address pointer for a given symbol.
Sym2Addr(string) (uintptr, error)
}
@@ -37,21 +39,49 @@ type SymbolResolution interface {
var SymbolResolver SymbolResolution
func init() {
- var err error
// First try the Linux location, since it's the most reliable.
- SymbolResolver, err = symtab.New("/proc/self/exe")
- if err == nil {
+ if r, err := symtab.New("/proc/self/exe"); err == nil {
+ SymbolResolver = NewSymbolCache(r)
return
}
// For other OS's this works in most cases we need. If it doesn't, log
// an error and keep going.
- SymbolResolver, err = symtab.New(os.Args[0])
- if err == nil {
+ if r, err := symtab.New(os.Args[0]); err == nil {
+ SymbolResolver = NewSymbolCache(r)
return
}
SymbolResolver = panicResolver(false)
}
+// SymbolCache added a caching layer over any SymbolResolution.
+type SymbolCache struct {
+ resolver SymbolResolution
+ cache map[string]uintptr
+ mu sync.Mutex
+}
+
+// NewSymbolCache adds caching to the given symbol resolver.
+func NewSymbolCache(r SymbolResolution) SymbolResolution {
+ return &SymbolCache{resolver: r, cache: make(map[string]uintptr)}
+}
+
+func (c *SymbolCache) Sym2Addr(sym string) (uintptr, error) {
+ c.mu.Lock()
+ defer c.mu.Unlock()
+
+ if p, exists := c.cache[sym]; exists {
+ return p, nil
+ }
+
+ p, err := c.resolver.Sym2Addr(sym)
+ if err != nil {
+ return 0, err
+ }
+
+ c.cache[sym] = p
+ return p, nil
+}
+
type panicResolver bool
func (p panicResolver) Sym2Addr(name string) (uintptr, error) {
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> symtab.go shouldn't read entire file into memory
> ------------------------------------------------
>
> Key: BEAM-3324
> URL: https://issues.apache.org/jira/browse/BEAM-3324
> Project: Beam
> Issue Type: Improvement
> Components: sdk-go
> Reporter: Bill Neubauer
> Assignee: Bill Neubauer
> Priority: Minor
>
> The implementation of symtab.go reads the entire binary into memory. This is
> wasteful of memory, and it should just use os.File as the backing reader. If
> performance becomes an issue, we can use a modest amount of memory to cache
> lookups and avoid filesystem reads.
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