runtime: avoid large object stack copy in traceStackTable.dump

Following up on the previous CL, this CL removes a unnecessary stack copy of a large object in a range loop. This drops another 64 KiB from (*traceStackTable).dump's stack frame so it is now roughly 80 bytes depending on architecture, which will easily fit on the system stack. For #53979. Change-Id: I16f642f6f1982d0ed0a62371bf2e19379e5870eb Reviewed-on: https://go-review.googlesource.com/c/go/+/422955 Reviewed-by: Michael Knyszek <[email protected]> TryBot-Result: Gopher Robot <[email protected]> Run-TryBot: Austin Clements <[email protected]>
golang · Aug 11, 2022 · 0293a1f · 0293a1f
1 parent d4a3466
commit 0293a1f
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/src/runtime/trace.go b/src/runtime/trace.go
@@ -1060,8 +1060,8 @@ func traceFrames(bufp traceBufPtr, pcs []uintptr) ([]traceFrame, traceBufPtr) {
 // releases all memory and resets state.
 func (tab *traceStackTable) dump() {
 	bufp := traceFlush(0, 0)
-	for _, stk := range tab.tab {
-		stk := stk.ptr()
+	for i, _ := range tab.tab {
+		stk := tab.tab[i].ptr()
 		for ; stk != nil; stk = stk.link.ptr() {
 			var frames []traceFrame
 			frames, bufp = traceFrames(bufp, stk.stack())