From: Francis Giraldeau <francis.giraldeau@gmail.com>
To: Chris Metcalf <cmetcalf@mellanox.com>,
Gilad Ben Yossef <giladb@mellanox.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>, Tejun Heo <tj@kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Christoph Lameter <cl@linux.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Andy Lutomirski <luto@amacapital.net>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
linux-doc@vger.kernel.org, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: Ping: [PATCH v15 00/13] support "task_isolation" mode
Date: Wed, 7 Sep 2016 17:11:06 -0400 [thread overview]
Message-ID: <057a958c-4491-b449-ae59-7d331afc872d@gmail.com> (raw)
In-Reply-To: <d00bbe64-6e2c-51ce-1dfb-72ef1c4a04fa@mellanox.com>
On 2016-08-29 12:27 PM, Chris Metcalf wrote:
> On 8/16/2016 5:19 PM, Chris Metcalf wrote:
>> Here is a respin of the task-isolation patch set.
>
> No concerns have been raised yet with the v15 version of the patch series
> in the two weeks since I posted it, and I think I have addressed all
> previously-raised concerns (or perhaps people have just given up arguing
> with me).
There is a cycle with header include in the v15 patch set on x86_64 that cause a compilation error. You will find the patch (and other fixes) in the following branch:
https://github.com/giraldeau/linux/commits/dataplane-x86-fix-inc
In the test file, it is indicated to change timer-tick.c to disable the 1Hz tick, is there a reason why the change is not in the patch set? I added this trivial change in the branch dataplane-x86-fix-inc above.
The syscall test fails on x86:
$ sudo ./isolation
[...]
test_syscall: FAIL (0x100)
test_syscall (SIGUSR1): FAIL (0x100)
I wanted to debug this problem with gdb and a KVM virtual machine. However, the TSC clock source is detected as non reliable, even with the boot parameter tsc=reliable, and therefore prctl(PR_SET_TASK_ISOLATION, PR_TASK_ISOLATION_ENABLE) always returns EAGAIN. Is there a trick to run task isolation in a VM (at least for debugging purposes)?
BTW, this was causing the test to enter an infinite loop. If the clock source is not reliable, maybe a different error code should be returned, because this situation not transient. In the mean time, I added a check for 100 max retries in the test (prctl_safe()).
When running only the test_jitter(), the isolation mode is lost:
[ 6741.566048] isolation/9515: task_isolation mode lost due to irq_work
With ftrace (events/workqueue/workqueue_execute_start), I get a bit more info:
kworker/1:1-676 [001] .... 6610.097128: workqueue_execute_start: work struct ffff8801a784ca20: function dbs_work_handler
The governor was ondemand, so I tried to set the frequency scaling governor to performance, but that does not solve the issue. Is there a way to suppress this irq_work? Should we run the isolated task with high real-time priority, such that it never get preempted?
Thanks!
Francis
next prev parent reply other threads:[~2016-09-07 21:11 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-16 21:19 [PATCH v15 00/13] support "task_isolation" mode Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 01/13] vmstat: add quiet_vmstat_sync function Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 02/13] vmstat: add vmstat_idle function Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 03/13] lru_add_drain_all: factor out lru_add_drain_needed Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 04/13] task_isolation: add initial support Chris Metcalf
2016-08-29 16:33 ` Peter Zijlstra
2016-08-29 16:40 ` Chris Metcalf
2016-08-29 16:48 ` Peter Zijlstra
2016-08-29 16:53 ` Chris Metcalf
2016-08-30 7:59 ` Peter Zijlstra
2016-08-30 7:58 ` Peter Zijlstra
2016-08-30 15:32 ` Chris Metcalf
2016-08-30 16:30 ` Andy Lutomirski
2016-08-30 17:02 ` Chris Metcalf
2016-08-30 18:43 ` Andy Lutomirski
2016-08-30 19:37 ` Chris Metcalf
2016-08-30 19:50 ` Andy Lutomirski
2016-09-02 14:04 ` Chris Metcalf
2016-09-02 17:28 ` Andy Lutomirski
2016-09-09 17:40 ` Chris Metcalf
2016-09-12 17:41 ` Andy Lutomirski
2016-09-12 19:25 ` Chris Metcalf
2016-09-27 14:22 ` Frederic Weisbecker
2016-09-27 14:39 ` Peter Zijlstra
2016-09-27 14:51 ` Frederic Weisbecker
2016-09-27 14:48 ` Paul E. McKenney
2016-09-30 16:59 ` Chris Metcalf
2016-09-01 10:06 ` Peter Zijlstra
2016-09-02 14:03 ` Chris Metcalf
2016-09-02 16:40 ` Peter Zijlstra
2017-02-02 16:13 ` Eugene Syromiatnikov
2017-02-02 18:12 ` Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 05/13] task_isolation: track asynchronous interrupts Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 06/13] arch/x86: enable task isolation functionality Chris Metcalf
2016-08-30 21:46 ` Andy Lutomirski
2016-08-16 21:19 ` [PATCH v15 07/13] arm64: factor work_pending state machine to C Chris Metcalf
2016-08-17 8:05 ` Will Deacon
2016-08-16 21:19 ` [PATCH v15 08/13] arch/arm64: enable task isolation functionality Chris Metcalf
2016-08-26 16:25 ` Catalin Marinas
2016-08-16 21:19 ` [PATCH v15 09/13] arch/tile: " Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 10/13] arm, tile: turn off timer tick for oneshot_stopped state Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 11/13] task_isolation: support CONFIG_TASK_ISOLATION_ALL Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 12/13] task_isolation: add user-settable notification signal Chris Metcalf
2016-08-16 21:19 ` [PATCH v15 13/13] task_isolation self test Chris Metcalf
2016-08-17 19:37 ` [PATCH] Fix /proc/stat freezes (was [PATCH v15] "task_isolation" mode) Christoph Lameter
2016-08-20 1:42 ` Chris Metcalf
2016-09-28 13:16 ` Frederic Weisbecker
2016-08-29 16:27 ` Ping: [PATCH v15 00/13] support "task_isolation" mode Chris Metcalf
2016-09-07 21:11 ` Francis Giraldeau [this message]
2016-09-07 21:39 ` Francis Giraldeau
2016-09-08 16:21 ` Francis Giraldeau
2016-09-12 16:01 ` Chris Metcalf
2016-09-12 16:14 ` Peter Zijlstra
2016-09-12 21:15 ` Rafael J. Wysocki
2016-09-13 0:05 ` Rafael J. Wysocki
2016-09-13 16:00 ` Francis Giraldeau
2016-09-13 0:20 ` Francis Giraldeau
2016-09-13 16:12 ` Chris Metcalf
2016-09-27 14:49 ` Frederic Weisbecker
2016-09-27 14:35 ` Frederic Weisbecker
2016-09-30 17:07 ` Chris Metcalf
2016-11-05 4:04 ` task isolation discussion at Linux Plumbers Chris Metcalf
2016-11-05 16:05 ` Christoph Lameter
2016-11-07 16:55 ` Thomas Gleixner
2016-11-07 18:36 ` Thomas Gleixner
2016-11-07 19:12 ` Rik van Riel
2016-11-07 19:16 ` Will Deacon
2016-11-07 19:18 ` Rik van Riel
2016-11-11 20:54 ` Luiz Capitulino
2016-11-09 1:40 ` Paul E. McKenney
2016-11-09 11:14 ` Andy Lutomirski
2016-11-09 17:38 ` Paul E. McKenney
2016-11-09 18:57 ` Will Deacon
2016-11-09 19:11 ` Paul E. McKenney
2016-11-10 1:44 ` Andy Lutomirski
2016-11-10 4:52 ` Paul E. McKenney
2016-11-10 5:10 ` Paul E. McKenney
2016-11-11 17:00 ` Andy Lutomirski
2016-11-09 11:07 ` Frederic Weisbecker
2016-12-19 14:37 ` Paul E. McKenney
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