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<title>litmus-rt.git/tools, branch 2012.2</title>
<subtitle>The LITMUS^RT kernel.</subtitle>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/'/>
<entry>
<title>Merge branches 'perf-urgent-for-linus', 'sched-urgent-for-linus', 'timers-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip</title>
<updated>2011-06-19T16:00:18+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2011-06-19T16:00:18+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=8816ead9d8e7c2745788e0684797e1912b504f33'/>
<id>8816ead9d8e7c2745788e0684797e1912b504f33</id>
<content type='text'>
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  tools/perf: Fix static build of perf tool
  tracing: Fix regression in printk_formats file

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  generic-ipi: Fix kexec boot crash by initializing call_single_queue before enabling interrupts

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  clocksource: Make watchdog robust vs. interruption
  timerfd: Fix wakeup of processes when timer is cancelled on clock change

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, MAINTAINERS: Add x86 MCE people
  x86, efi: Do not reserve boot services regions within reserved areas
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  tools/perf: Fix static build of perf tool
  tracing: Fix regression in printk_formats file

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  generic-ipi: Fix kexec boot crash by initializing call_single_queue before enabling interrupts

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  clocksource: Make watchdog robust vs. interruption
  timerfd: Fix wakeup of processes when timer is cancelled on clock change

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, MAINTAINERS: Add x86 MCE people
  x86, efi: Do not reserve boot services regions within reserved areas
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip</title>
<updated>2011-06-19T15:56:56+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2011-06-19T15:56:56+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=357ed6b1a110048ff8106f99092d6c4a7aadb45a'/>
<id>357ed6b1a110048ff8106f99092d6c4a7aadb45a</id>
<content type='text'>
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rcu: Move RCU_BOOST #ifdefs to header file
  rcu: use softirq instead of kthreads except when RCU_BOOST=y
  rcu: Use softirq to address performance regression
  rcu: Simplify curing of load woes
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rcu: Move RCU_BOOST #ifdefs to header file
  rcu: use softirq instead of kthreads except when RCU_BOOST=y
  rcu: Use softirq to address performance regression
  rcu: Simplify curing of load woes
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6</title>
<updated>2011-06-16T17:26:58+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2011-06-16T17:26:58+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=7cc2ed05891f424c2e323bc1a368ddb5c78b90f2'/>
<id>7cc2ed05891f424c2e323bc1a368ddb5c78b90f2</id>
<content type='text'>
* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
  kbuild: Call depmod.sh via shell
  perf: clear out make flags when calling kernel make kernelver
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
  kbuild: Call depmod.sh via shell
  perf: clear out make flags when calling kernel make kernelver
</pre>
</div>
</content>
</entry>
<entry>
<title>tools/perf: Fix static build of perf tool</title>
<updated>2011-06-16T08:17:39+00:00</updated>
<author>
<name>Mathias Krause</name>
<email>minipli@googlemail.com</email>
</author>
<published>2011-06-15T21:03:38+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=203db2952bc87f5d610c9ad53a7d02b85897721f'/>
<id>203db2952bc87f5d610c9ad53a7d02b85897721f</id>
<content type='text'>
To build a statically linked version of the perf tool all needed
libraries must be added in the correct order to get the symbols
resolved. Currently this is broken when, e.g. python or newt
support is enabled -- libpython needs libpthread which is an
unconditional link dependency of the perf tool; libslang needs
libm, another unconditional dependency. To solve the problem in
the long run without the need to keep track of transitive
library dependencies, simply make the linker look at the EXTLIBS
multiple times until it has all symbols resolved.

Signed-off-by: Mathias Krause &lt;minipli@googlemail.com&gt;
Cc: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@ghostprotocols.net&gt;
Link: http://lkml.kernel.org/r/1308171818-20370-1-git-send-email-minipli@googlemail.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
To build a statically linked version of the perf tool all needed
libraries must be added in the correct order to get the symbols
resolved. Currently this is broken when, e.g. python or newt
support is enabled -- libpython needs libpthread which is an
unconditional link dependency of the perf tool; libslang needs
libm, another unconditional dependency. To solve the problem in
the long run without the need to keep track of transitive
library dependencies, simply make the linker look at the EXTLIBS
multiple times until it has all symbols resolved.

Signed-off-by: Mathias Krause &lt;minipli@googlemail.com&gt;
Cc: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@ghostprotocols.net&gt;
Link: http://lkml.kernel.org/r/1308171818-20370-1-git-send-email-minipli@googlemail.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf: clear out make flags when calling kernel make kernelver</title>
<updated>2011-06-15T20:12:55+00:00</updated>
<author>
<name>Andy Whitcroft</name>
<email>apw@canonical.com</email>
</author>
<published>2011-06-15T13:35:00+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=37aa9a2eb4d9b1a4aec1fd18bb2bb6bca029de27'/>
<id>37aa9a2eb4d9b1a4aec1fd18bb2bb6bca029de27</id>
<content type='text'>
When generating the perf version from the kernel version using 'make
kernelver' it is necessary to clear out any MAKEFLAGS otherwise they may
trigger additional output which pollute the contents.

Signed-off-by: Andy Whitcroft &lt;apw@canonical.com&gt;
Signed-off-by: Michal Marek &lt;mmarek@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When generating the perf version from the kernel version using 'make
kernelver' it is necessary to clear out any MAKEFLAGS otherwise they may
trigger additional output which pollute the contents.

Signed-off-by: Andy Whitcroft &lt;apw@canonical.com&gt;
Signed-off-by: Michal Marek &lt;mmarek@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rcu: Use softirq to address performance regression</title>
<updated>2011-06-14T22:25:39+00:00</updated>
<author>
<name>Shaohua Li</name>
<email>shaohua.li@intel.com</email>
</author>
<published>2011-06-14T05:26:25+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=09223371deac67d08ca0b70bd18787920284c967'/>
<id>09223371deac67d08ca0b70bd18787920284c967</id>
<content type='text'>
Commit a26ac2455ffcf3(rcu: move TREE_RCU from softirq to kthread)
introduced performance regression. In an AIM7 test, this commit degraded
performance by about 40%.

The commit runs rcu callbacks in a kthread instead of softirq. We observed
high rate of context switch which is caused by this. Out test system has
64 CPUs and HZ is 1000, so we saw more than 64k context switch per second
which is caused by RCU's per-CPU kthread.  A trace showed that most of
the time the RCU per-CPU kthread doesn't actually handle any callbacks,
but instead just does a very small amount of work handling grace periods.
This means that RCU's per-CPU kthreads are making the scheduler do quite
a bit of work in order to allow a very small amount of RCU-related
processing to be done.

Alex Shi's analysis determined that this slowdown is due to lock
contention within the scheduler.  Unfortunately, as Peter Zijlstra points
out, the scheduler's real-time semantics require global action, which
means that this contention is inherent in real-time scheduling.  (Yes,
perhaps someone will come up with a workaround -- otherwise, -rt is not
going to do well on large SMP systems -- but this patch will work around
this issue in the meantime.  And "the meantime" might well be forever.)

This patch therefore re-introduces softirq processing to RCU, but only
for core RCU work.  RCU callbacks are still executed in kthread context,
so that only a small amount of RCU work runs in softirq context in the
common case.  This should minimize ksoftirqd execution, allowing us to
skip boosting of ksoftirqd for CONFIG_RCU_BOOST=y kernels.

Signed-off-by: Shaohua Li &lt;shaohua.li@intel.com&gt;
Tested-by: "Alex,Shi" &lt;alex.shi@intel.com&gt;
Signed-off-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit a26ac2455ffcf3(rcu: move TREE_RCU from softirq to kthread)
introduced performance regression. In an AIM7 test, this commit degraded
performance by about 40%.

The commit runs rcu callbacks in a kthread instead of softirq. We observed
high rate of context switch which is caused by this. Out test system has
64 CPUs and HZ is 1000, so we saw more than 64k context switch per second
which is caused by RCU's per-CPU kthread.  A trace showed that most of
the time the RCU per-CPU kthread doesn't actually handle any callbacks,
but instead just does a very small amount of work handling grace periods.
This means that RCU's per-CPU kthreads are making the scheduler do quite
a bit of work in order to allow a very small amount of RCU-related
processing to be done.

Alex Shi's analysis determined that this slowdown is due to lock
contention within the scheduler.  Unfortunately, as Peter Zijlstra points
out, the scheduler's real-time semantics require global action, which
means that this contention is inherent in real-time scheduling.  (Yes,
perhaps someone will come up with a workaround -- otherwise, -rt is not
going to do well on large SMP systems -- but this patch will work around
this issue in the meantime.  And "the meantime" might well be forever.)

This patch therefore re-introduces softirq processing to RCU, but only
for core RCU work.  RCU callbacks are still executed in kthread context,
so that only a small amount of RCU work runs in softirq context in the
common case.  This should minimize ksoftirqd execution, allowing us to
skip boosting of ksoftirqd for CONFIG_RCU_BOOST=y kernels.

Signed-off-by: Shaohua Li &lt;shaohua.li@intel.com&gt;
Tested-by: "Alex,Shi" &lt;alex.shi@intel.com&gt;
Signed-off-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6</title>
<updated>2011-06-09T23:27:42+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2011-06-09T23:27:42+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=6aecceccf5aa626b0af203e54ca62cbf308c53d8'/>
<id>6aecceccf5aa626b0af203e54ca62cbf308c53d8</id>
<content type='text'>
* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
  perf: Use make kernelversion instead of parsing the Makefile
  kbuild: Hack for depmod not handling X.Y versions
  kbuild: Move depmod call to a separate script
  kbuild: Fix &lt;linux/version.h&gt; for empty SUBLEVEL or PATCHLEVEL
  kbuild: Fix KERNELVERSION for empty SUBLEVEL or PATCHLEVEL
  kbuild: silence Nothing to be done for 'all' message
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
  perf: Use make kernelversion instead of parsing the Makefile
  kbuild: Hack for depmod not handling X.Y versions
  kbuild: Move depmod call to a separate script
  kbuild: Fix &lt;linux/version.h&gt; for empty SUBLEVEL or PATCHLEVEL
  kbuild: Fix KERNELVERSION for empty SUBLEVEL or PATCHLEVEL
  kbuild: silence Nothing to be done for 'all' message
</pre>
</div>
</content>
</entry>
<entry>
<title>perf: Use make kernelversion instead of parsing the Makefile</title>
<updated>2011-06-09T21:05:54+00:00</updated>
<author>
<name>Michal Marek</name>
<email>mmarek@suse.cz</email>
</author>
<published>2011-05-30T12:12:09+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=5d61b9fd19d9f3cf653dbba615876e7792eea5ea'/>
<id>5d61b9fd19d9f3cf653dbba615876e7792eea5ea</id>
<content type='text'>
Cc: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@ghostprotocols.net&gt;
Signed-off-by: Michal Marek &lt;mmarek@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Cc: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@ghostprotocols.net&gt;
Signed-off-by: Michal Marek &lt;mmarek@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip</title>
<updated>2011-06-08T15:36:15+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2011-06-08T15:36:15+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=33726bf2140a0e7c9de3ccd7cba6d69962f0b773'/>
<id>33726bf2140a0e7c9de3ccd7cba6d69962f0b773</id>
<content type='text'>
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf: Fix comments in include/linux/perf_event.h
  perf: Comment /proc/sys/kernel/perf_event_paranoid to be part of user ABI
  perf python: Fix argument name list of read_on_cpu()
  perf evlist: Don't die if sample_{id_all|type} is invalid
  perf python: Use exception to propagate errors
  perf evlist: Remove dependency on debug routines
  perf, cgroups: Fix up for new API
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf: Fix comments in include/linux/perf_event.h
  perf: Comment /proc/sys/kernel/perf_event_paranoid to be part of user ABI
  perf python: Fix argument name list of read_on_cpu()
  perf evlist: Don't die if sample_{id_all|type} is invalid
  perf python: Use exception to propagate errors
  perf evlist: Remove dependency on debug routines
  perf, cgroups: Fix up for new API
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-ktest</title>
<updated>2011-06-03T22:58:48+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2011-06-03T22:58:48+00:00</published>
<link rel='alternate' type='text/html' href='http://rtsrv.cs.unc.edu/cgit/cgit.cgi/litmus-rt.git/commit/?id=9a44fde3435e0c6012cbc9122497bbbd3338434a'/>
<id>9a44fde3435e0c6012cbc9122497bbbd3338434a</id>
<content type='text'>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-ktest:
  ktest: Ignore unset values of the minconfig in config_bisect
  ktest: Fix result of rebooting the kernel
  ktest: Fix off-by-one in config bisect result
</content>
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<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-ktest:
  ktest: Ignore unset values of the minconfig in config_bisect
  ktest: Fix result of rebooting the kernel
  ktest: Fix off-by-one in config bisect result
</pre>
</div>
</content>
</entry>
</feed>
