From: Austin Clements <austin@google.com>
Date: Tue, 7 Mar 2017 20:36:49 +0000 (-0500)
Subject: runtime: join selectgo and selectgoImpl
X-Git-Tag: go1.9beta1~1241
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=d50f892abca46b794a23f20777c0b2425467d407;p=gostls13.git

runtime: join selectgo and selectgoImpl

Currently selectgo is just a wrapper around selectgoImpl. This keeps
the hard-coded frame skip counts for tracing the same between the
channel implementation and the select implementation.

However, this is fragile and confusing, so pass a skip parameter to
send and recv, join selectgo and selectgoImpl into one function, and
use decrease all of the skips in selectgo by one.

Change-Id: I11b8cbb7d805b55f5dc6ab4875ac7dde79412ff2
Reviewed-on: https://go-review.googlesource.com/37860
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
---

diff --git a/src/runtime/chan.go b/src/runtime/chan.go
index b54a46cd2b..e74cd8b93d 100644
--- a/src/runtime/chan.go
+++ b/src/runtime/chan.go
@@ -183,7 +183,7 @@ func chansend(t *chantype, c *hchan, ep unsafe.Pointer, block bool, callerpc uin
 	if sg := c.recvq.dequeue(); sg != nil {
 		// Found a waiting receiver. We pass the value we want to send
 		// directly to the receiver, bypassing the channel buffer (if any).
-		send(c, sg, ep, func() { unlock(&c.lock) })
+		send(c, sg, ep, func() { unlock(&c.lock) }, 3)
 		return true
 	}
 
@@ -254,7 +254,7 @@ func chansend(t *chantype, c *hchan, ep unsafe.Pointer, block bool, callerpc uin
 // Channel c must be empty and locked.  send unlocks c with unlockf.
 // sg must already be dequeued from c.
 // ep must be non-nil and point to the heap or the caller's stack.
-func send(c *hchan, sg *sudog, ep unsafe.Pointer, unlockf func()) {
+func send(c *hchan, sg *sudog, ep unsafe.Pointer, unlockf func(), skip int) {
 	if raceenabled {
 		if c.dataqsiz == 0 {
 			racesync(c, sg)
@@ -284,7 +284,7 @@ func send(c *hchan, sg *sudog, ep unsafe.Pointer, unlockf func()) {
 	if sg.releasetime != 0 {
 		sg.releasetime = cputicks()
 	}
-	goready(gp, 4)
+	goready(gp, skip+1)
 }
 
 // Sends and receives on unbuffered or empty-buffered channels are the
@@ -464,7 +464,7 @@ func chanrecv(t *chantype, c *hchan, ep unsafe.Pointer, block bool) (selected, r
 		// directly from sender. Otherwise, receive from head of queue
 		// and add sender's value to the tail of the queue (both map to
 		// the same buffer slot because the queue is full).
-		recv(c, sg, ep, func() { unlock(&c.lock) })
+		recv(c, sg, ep, func() { unlock(&c.lock) }, 3)
 		return true, true
 	}
 
@@ -540,7 +540,7 @@ func chanrecv(t *chantype, c *hchan, ep unsafe.Pointer, block bool) (selected, r
 // Channel c must be full and locked. recv unlocks c with unlockf.
 // sg must already be dequeued from c.
 // A non-nil ep must point to the heap or the caller's stack.
-func recv(c *hchan, sg *sudog, ep unsafe.Pointer, unlockf func()) {
+func recv(c *hchan, sg *sudog, ep unsafe.Pointer, unlockf func(), skip int) {
 	if c.dataqsiz == 0 {
 		if raceenabled {
 			racesync(c, sg)
@@ -580,7 +580,7 @@ func recv(c *hchan, sg *sudog, ep unsafe.Pointer, unlockf func()) {
 	if sg.releasetime != 0 {
 		sg.releasetime = cputicks()
 	}
-	goready(gp, 4)
+	goready(gp, skip+1)
 }
 
 // compiler implements
diff --git a/src/runtime/select.go b/src/runtime/select.go
index 03b699796f..715cee8750 100644
--- a/src/runtime/select.go
+++ b/src/runtime/select.go
@@ -199,13 +199,7 @@ func block() {
 //
 // selectgo returns the index of the chosen scase, which matches the
 // ordinal position of its respective select{recv,send,default} call.
-//go:nosplit
 func selectgo(sel *hselect) int {
-	return selectgoImpl(sel)
-}
-
-// Separate function to keep runtime/trace.TestTraceSymbolize happy.
-func selectgoImpl(sel *hselect) int {
 	if debugSelect {
 		print("select: sel=", sel, "\n")
 	}
@@ -398,7 +392,7 @@ loop:
 
 	// wait for someone to wake us up
 	gp.param = nil
-	gopark(selparkcommit, nil, "select", traceEvGoBlockSelect, 2)
+	gopark(selparkcommit, nil, "select", traceEvGoBlockSelect, 1)
 
 	// While we were asleep, some goroutine came along and completed
 	// one of the cases in the select and woke us up (called ready).
@@ -592,7 +586,7 @@ bufsend:
 
 recv:
 	// can receive from sleeping sender (sg)
-	recv(c, sg, cas.elem, func() { selunlock(scases, lockorder) })
+	recv(c, sg, cas.elem, func() { selunlock(scases, lockorder) }, 2)
 	if debugSelect {
 		print("syncrecv: sel=", sel, " c=", c, "\n")
 	}
@@ -623,7 +617,7 @@ send:
 	if msanenabled {
 		msanread(cas.elem, c.elemtype.size)
 	}
-	send(c, sg, cas.elem, func() { selunlock(scases, lockorder) })
+	send(c, sg, cas.elem, func() { selunlock(scases, lockorder) }, 2)
 	if debugSelect {
 		print("syncsend: sel=", sel, " c=", c, "\n")
 	}
@@ -631,7 +625,7 @@ send:
 
 retc:
 	if cas.releasetime > 0 {
-		blockevent(cas.releasetime-t0, 2)
+		blockevent(cas.releasetime-t0, 1)
 	}
 	return casi