From fa698123dc22fba09054c8869341da314919831a Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Wed, 18 Sep 2019 22:58:21 -0700
Subject: [PATCH] modules/console: Add bare metal latency as control result.

---
 modules/console.cc | 113 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 96 insertions(+), 17 deletions(-)

diff --git a/modules/console.cc b/modules/console.cc
index 7fc5fb030..725f0685d 100644
--- a/modules/console.cc
+++ b/modules/console.cc
@@ -1352,20 +1352,69 @@ console_cmd__ios(opt &out, const string_view &line)
 	return true;
 }
 
+#ifdef __x86_64__
 bool
 console_cmd__ios__latency(opt &out, const string_view &line)
 {
-	auto returned(0UL);
-	auto executed(0UL);
-	auto started(0UL);
+	volatile long long returned, executed, started;
+
+	// control
+	{
+		__sync_synchronize();
+		asm volatile ("lfence" :::);
+		started = prof::cycles();
+		asm volatile ("lfence" :::);
+		executed = prof::cycles();
+		asm volatile ("lfence" :::);
+		returned = prof::cycles();
+		asm volatile ("lfence" :::);
+	}
+
+	out
+	<< "bare send:    "  << (executed - started)    << std::endl
+	<< "bare recv:    "  << (returned - executed)   << std::endl
+	<< "bare rtt:     "  << (returned - started)    << std::endl
+	<< std::endl;
+
+	// control
+	{
+		__sync_synchronize();
+		started = prof::x86::rdtscp();
+		asm volatile ("lfence" :::);
+		executed = prof::x86::rdtscp();
+		asm volatile ("lfence" :::);
+		returned = prof::x86::rdtscp();
+		asm volatile ("lfence" :::);
+	}
+
+	out
+	<< "tscp send:    "  << (executed - started)    << std::endl
+	<< "tscp recv:    "  << (returned - executed)   << std::endl
+	<< "tscp rtt:     "  << (returned - started)    << std::endl
+	<< std::endl;
+
+	//
+	// ios::dispatch
+	//
 
 	{
+		__sync_synchronize();
+		asm volatile ("lfence" :::);
 		started = prof::cycles();
+		asm volatile ("lfence" :::);
+
 		ios::dispatch(ios::synchronous, [&executed]
 		{
+			__sync_synchronize();
+			asm volatile ("lfence" :::);
 			executed = prof::cycles();
+			asm volatile ("lfence" :::);
 		});
+
+		__sync_synchronize();
+		asm volatile ("lfence" :::);
 		returned = prof::cycles();
+		asm volatile ("lfence" :::);
 	}
 
 	out
@@ -1374,28 +1423,28 @@ console_cmd__ios__latency(opt &out, const string_view &line)
 	<< "disp rtt:     "  << (returned - started)    << std::endl
 	<< std::endl;
 
-	{
-		started = prof::cycles();
-		ios::post(ios::synchronous, [&executed]
-		{
-			executed = prof::cycles();
-		});
-		returned = prof::cycles();
-	}
-
-	out
-	<< "post send:    "  << (executed - started)    << std::endl
-	<< "post recv:    "  << (returned - executed)   << std::endl
-	<< "post rtt:     "  << (returned - started)    << std::endl
-	<< std::endl;
+	//
+	// ios::defer
+	//
 
 	{
+		__sync_synchronize();
+		asm volatile ("lfence" :::);
 		started = prof::cycles();
+		asm volatile ("lfence" :::);
+
 		ios::defer(ios::synchronous, [&executed]
 		{
+			__sync_synchronize();
+			asm volatile ("lfence" :::);
 			executed = prof::cycles();
+			asm volatile ("lfence" :::);
 		});
+
+		__sync_synchronize();
+		asm volatile ("lfence" :::);
 		returned = prof::cycles();
+		asm volatile ("lfence" :::);
 	}
 
 	out
@@ -1404,9 +1453,39 @@ console_cmd__ios__latency(opt &out, const string_view &line)
 	<< "defer rtt:    "  << (returned - started)    << std::endl
 	<< std::endl;
 
+	//
+	// ios::post
+	//
+
+	{
+		__sync_synchronize();
+		asm volatile ("lfence" :::);
+		started = prof::cycles();
+		asm volatile ("lfence" :::);
+
+		ios::post(ios::synchronous, [&executed]
+		{
+			__sync_synchronize();
+			asm volatile ("lfence" :::);
+			executed = prof::cycles();
+			asm volatile ("lfence" :::);
+		});
+
+		__sync_synchronize();
+		asm volatile ("lfence" :::);
+		returned = prof::cycles();
+		asm volatile ("lfence" :::);
+	}
+
+	out
+	<< "post send:    "  << (executed - started)    << std::endl
+	<< "post recv:    "  << (returned - executed)   << std::endl
+	<< "post rtt:     "  << (returned - started)    << std::endl
+	<< std::endl;
 
 	return true;
 }
+#endif
 
 //
 // aio