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authorLinus Torvalds <torvalds@linux-foundation.org>2014-08-05 17:46:42 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-05 17:46:42 -0700
commite7fda6c4c3c1a7d6996dd75fd84670fa0b5d448f (patch)
treedaa51c16462c318b890acf7f01fba5827275dd74 /tools
parent08d69a25714429850cf9ef71f22d8cdc9189d93f (diff)
parent953dec21aed4038464fec02f96a2f1b8701a5bce (diff)
downloadlinux-e7fda6c4c3c1a7d6996dd75fd84670fa0b5d448f.tar.bz2
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer and time updates from Thomas Gleixner: "A rather large update of timers, timekeeping & co - Core timekeeping code is year-2038 safe now for 32bit machines. Now we just need to fix all in kernel users and the gazillion of user space interfaces which rely on timespec/timeval :) - Better cache layout for the timekeeping internal data structures. - Proper nanosecond based interfaces for in kernel users. - Tree wide cleanup of code which wants nanoseconds but does hoops and loops to convert back and forth from timespecs. Some of it definitely belongs into the ugly code museum. - Consolidation of the timekeeping interface zoo. - A fast NMI safe accessor to clock monotonic for tracing. This is a long standing request to support correlated user/kernel space traces. With proper NTP frequency correction it's also suitable for correlation of traces accross separate machines. - Checkpoint/restart support for timerfd. - A few NOHZ[_FULL] improvements in the [hr]timer code. - Code move from kernel to kernel/time of all time* related code. - New clocksource/event drivers from the ARM universe. I'm really impressed that despite an architected timer in the newer chips SoC manufacturers insist on inventing new and differently broken SoC specific timers. [ Ed. "Impressed"? I don't think that word means what you think it means ] - Another round of code move from arch to drivers. Looks like most of the legacy mess in ARM regarding timers is sorted out except for a few obnoxious strongholds. - The usual updates and fixlets all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits) timekeeping: Fixup typo in update_vsyscall_old definition clocksource: document some basic timekeeping concepts timekeeping: Use cached ntp_tick_length when accumulating error timekeeping: Rework frequency adjustments to work better w/ nohz timekeeping: Minor fixup for timespec64->timespec assignment ftrace: Provide trace clocks monotonic timekeeping: Provide fast and NMI safe access to CLOCK_MONOTONIC seqcount: Add raw_write_seqcount_latch() seqcount: Provide raw_read_seqcount() timekeeping: Use tk_read_base as argument for timekeeping_get_ns() timekeeping: Create struct tk_read_base and use it in struct timekeeper timekeeping: Restructure the timekeeper some more clocksource: Get rid of cycle_last clocksource: Move cycle_last validation to core code clocksource: Make delta calculation a function wireless: ath9k: Get rid of timespec conversions drm: vmwgfx: Use nsec based interfaces drm: i915: Use nsec based interfaces timekeeping: Provide ktime_get_raw() hangcheck-timer: Use ktime_get_ns() ...
Diffstat (limited to 'tools')
-rwxr-xr-xtools/time/udelay_test.sh66
1 files changed, 66 insertions, 0 deletions
diff --git a/tools/time/udelay_test.sh b/tools/time/udelay_test.sh
new file mode 100755
index 000000000000..12d46b926917
--- /dev/null
+++ b/tools/time/udelay_test.sh
@@ -0,0 +1,66 @@
+#!/bin/bash
+
+# udelay() test script
+#
+# Test is executed by writing and reading to /sys/kernel/debug/udelay_test
+# and exercises a variety of delays to ensure that udelay() is delaying
+# at least as long as requested (as compared to ktime).
+#
+# Copyright (C) 2014 Google, Inc.
+#
+# This software is licensed under the terms of the GNU General Public
+# License version 2, as published by the Free Software Foundation, and
+# may be copied, distributed, and modified under those terms.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+
+MODULE_NAME=udelay_test
+UDELAY_PATH=/sys/kernel/debug/udelay_test
+
+setup()
+{
+ /sbin/modprobe -q $MODULE_NAME
+ tmp_file=`mktemp`
+}
+
+test_one()
+{
+ delay=$1
+ echo $delay > $UDELAY_PATH
+ tee -a $tmp_file < $UDELAY_PATH
+}
+
+cleanup()
+{
+ if [ -f $tmp_file ]; then
+ rm $tmp_file
+ fi
+ /sbin/modprobe -q -r $MODULE_NAME
+}
+
+trap cleanup EXIT
+setup
+
+# Delay for a variety of times.
+# 1..200, 200..500 (by 10), 500..2000 (by 100)
+for (( delay = 1; delay < 200; delay += 1 )); do
+ test_one $delay
+done
+for (( delay = 200; delay < 500; delay += 10 )); do
+ test_one $delay
+done
+for (( delay = 500; delay <= 2000; delay += 100 )); do
+ test_one $delay
+done
+
+# Search for failures
+count=`grep -c FAIL $tmp_file`
+if [ $? -eq "0" ]; then
+ echo "ERROR: $count delays failed to delay long enough"
+ retcode=1
+fi
+
+exit $retcode