From eaf4150c7bc0d12b1b1f39d1e257cdb56bfa165a Mon Sep 17 00:00:00 2001
From: Martin Stein <martin.stein@genode-labs.com>
Date: Tue, 7 Jul 2015 17:17:20 +0200
Subject: [PATCH] cpu_quota.run: support X86

The timer driver on X86 needs CPU quota with highest priority as it
frequently has to interrupt the counters to update the PIT.
On ARM this makes no difference in the test results as ARM timer
drivers, once configured, can sleep until the end of the timeouts.
On X86 we raise the error tolerance to 2% (default 1%) to compensate
the error caused by the timer.

Fixes #1621
---
 repos/os/run/cpu_quota.run | 42 +++++++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/repos/os/run/cpu_quota.run b/repos/os/run/cpu_quota.run
index c474ff4344..c031e1fa2e 100644
--- a/repos/os/run/cpu_quota.run
+++ b/repos/os/run/cpu_quota.run
@@ -2,15 +2,8 @@
 # Check platform
 #
 # HW is the only kernel that provides appliance of quota to the scheduling.
-# On X86, the timer driver uses the PIT with a timeout of max. 54 ms. Thus,
-# the driver needs to restart the timer permanently which is a hard job with 6
-# high-priority counter-threads in the background. As a consequence, timeouts
-# take much longer than requested and the test fails.  However, as the PIT
-# tends to be replaced by a better timing source, we simply skip X86 for now.
-#
 #
 assert_spec hw
-assert_spec arm
 
 #
 # Build
@@ -43,11 +36,6 @@ install_config {
 		<any-service><parent/><any-child/></any-service>
 	</default-route>
 
-	<start name="timer">
-		<resource name="RAM" quantum="10M"/>
-		<provides><service name="Timer"/></provides>
-	</start>
-
 	<start name="test-sync">
 		<resource name="RAM" quantum="10M"/>
 		<provides><service name="Sync"/></provides>
@@ -55,9 +43,9 @@ install_config {
 
 	<start name="init_1" priority="-1">
 		<binary name="init"/>
-		<resource name="RAM" quantum="10M"/>
+		<resource name="RAM" quantum="20M"/>
 		<resource name="CPU" quantum="10"/>
-		<config prio_levels="2">
+		<config>
 			<parent-provides>
 				<service name="ROM"/>
 				<service name="RAM"/>
@@ -77,7 +65,7 @@ install_config {
 				<any-service><parent/><any-child/></any-service>
 			</default-route>
 
-			<start name="test_slow" priority="-1">
+			<start name="test_slow">
 				<binary name="test-cpu_quota"/>
 				<resource name="RAM" quantum="10M"/>
 				<resource name="CPU" quantum="50"/>
@@ -88,9 +76,9 @@ install_config {
 
 	<start name="init_2" priority="-2">
 		<binary name="init"/>
-		<resource name="RAM" quantum="100M"/>
+		<resource name="RAM" quantum="30M"/>
 		<resource name="CPU" quantum="80"/>
-		<config>
+		<config prio_levels="2">
 			<parent-provides>
 				<service name="ROM"/>
 				<service name="RAM"/>
@@ -110,13 +98,13 @@ install_config {
 				<any-service><parent/></any-service>
 			</default-route>
 
-			<start name="test_midl">
+			<start name="test_midl" priority="0">
 				<binary name="test-cpu_quota"/>
 				<resource name="RAM" quantum="10M"/>
 				<resource name="CPU" quantum="25"/>
 			</start>
 
-			<start name="test_fast">
+			<start name="test_fast" priority="-1">
 				<binary name="test-cpu_quota"/>
 				<resource name="RAM" quantum="10M"/>
 				<resource name="CPU" quantum="75"/>
@@ -124,6 +112,13 @@ install_config {
 
 		</config>
 	</start>
+
+	<start name="timer" priority="0">
+		<resource name="RAM" quantum="10M"/>
+		<resource name="CPU" quantum="10"/>
+		<provides><service name="Timer"/></provides>
+	</start>
+
 </config>
 }
 
@@ -149,6 +144,15 @@ proc check_counter { name opt cnt total_cnt } {
 	set    err     0.01
 	set    is      0
 
+	#
+	# On X86, the timer driver uses the PIT with a maximum timeout of 54 ms.
+	# Thus, the driver frequently interrupts the counters with highest
+	# priority to update the timer. This is why we need a higher error
+	# tolerance as for ARM where the driver, once configured, can sleep for
+	# the whole test timeout.
+	#
+	if {[have_spec x86]} { set err 0.02 }
+
 	if {[expr $total_cnt != 0]} { set is [expr double($cnt) / $total_cnt ] }
 
 	set is_pc  [expr double(round($is  * 100000)) / 1000]