From: Pavel Machek <pavel@ucw.cz>
To: Alex Belits <abelits@marvell.com>
Cc: "nitesh@redhat.com" <nitesh@redhat.com>,
"frederic@kernel.org" <frederic@kernel.org>,
Prasun Kapoor <pkapoor@marvell.com>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"trix@redhat.com" <trix@redhat.com>,
"mingo@kernel.org" <mingo@kernel.org>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"peterx@redhat.com" <peterx@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"mtosatti@redhat.com" <mtosatti@redhat.com>,
"will@kernel.org" <will@kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"leon@sidebranch.com" <leon@sidebranch.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"pauld@redhat.com" <pauld@redhat.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH v5 0/9] "Task_isolation" mode
Date: Sat, 5 Dec 2020 21:40:49 +0100 [thread overview]
Message-ID: <20201205204049.GA8578@amd> (raw)
In-Reply-To: <8d887e59ca713726f4fcb25a316e1e932b02823e.camel@marvell.com>
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Hi!
> General description
>
> This is the result of development and maintenance of task isolation
> functionality that originally started based on task isolation patch
> v15 and was later updated to include v16. It provided predictable
> environment for userspace tasks running on arm64 processors alongside
> with full-featured Linux environment. It is intended to provide
> reliable interruption-free environment from the point when a userspace
> task enters isolation and until the moment it leaves isolation or
> receives a signal intentionally sent to it, and was successfully used
> for this purpose. While CPU isolation with nohz provides an
> environment that is close to this requirement, the remaining IPIs and
> other disturbances keep it from being usable for tasks that require
> complete predictability of CPU timing.
So... what kind of guarantees does this aim to provide / what tasks it
is useful for?
For real time response, we have other approaches.
If you want to guarantee performnace of the "isolated" task... I don't
see how that works. Other tasks on the system still compete for DRAM
bandwidth, caches, etc...
So... what is the usecase?
Pavel
--
http://www.livejournal.com/~pavelmachek
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next prev parent reply other threads:[~2020-12-05 20:41 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-23 17:42 [PATCH v5 0/9] "Task_isolation" mode Alex Belits
2020-11-23 17:56 ` [PATCH v5 1/9] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits
2020-11-23 21:48 ` Thomas Gleixner
2020-11-23 17:56 ` [PATCH v5 2/9] task_isolation: vmstat: add vmstat_idle function Alex Belits
2020-11-23 21:49 ` Thomas Gleixner
2020-11-23 17:56 ` [PATCH v5 3/9] task_isolation: userspace hard isolation from kernel Alex Belits
2020-11-23 22:01 ` Thomas Gleixner
2020-11-23 17:57 ` [PATCH v5 4/9] task_isolation: Add task isolation hooks to arch-independent code Alex Belits
2020-11-23 22:31 ` Thomas Gleixner
2020-11-23 17:57 ` [PATCH v5 5/9] task_isolation: Add driver-specific hooks Alex Belits
2020-12-02 14:18 ` Mark Rutland
2020-12-04 0:43 ` [EXT] " Alex Belits
2020-11-23 17:58 ` [PATCH v5 6/9] task_isolation: arch/arm64: enable task isolation functionality Alex Belits
2020-12-02 13:59 ` Mark Rutland
2020-12-04 0:37 ` [EXT] " Alex Belits
2020-12-07 11:57 ` Mark Rutland
2020-11-23 17:58 ` [PATCH v5 7/9] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits
2020-11-23 22:13 ` Frederic Weisbecker
2020-11-23 22:35 ` Alex Belits
2020-11-23 22:36 ` Thomas Gleixner
2020-12-02 14:20 ` Mark Rutland
2020-12-04 0:54 ` [EXT] " Alex Belits
2020-12-07 11:58 ` Mark Rutland
2020-11-23 17:58 ` [PATCH v5 8/9] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits
2020-11-23 17:58 ` [PATCH v5 9/9] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits
2020-11-23 22:29 ` Frederic Weisbecker
2020-11-23 22:39 ` [EXT] " Alex Belits
2020-11-23 23:21 ` Frederic Weisbecker
2020-11-25 3:20 ` Alex Belits
2021-01-22 15:00 ` Marcelo Tosatti
2020-11-24 16:36 ` [PATCH v5 0/9] "Task_isolation" mode Tom Rix
2020-11-24 17:40 ` [EXT] " Alex Belits
2020-12-02 14:02 ` Mark Rutland
2020-12-04 0:39 ` Alex Belits
2020-12-05 20:40 ` Pavel Machek [this message]
2020-12-05 23:25 ` Thomas Gleixner
2020-12-11 18:08 ` Yury Norov
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