Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 22 Jan 2020 12:16:32 -0500 (EST)
From:   Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To:     Jan Ziak <0xe2.0x9a.0x9b@gmail.com>
Cc:     Andi Kleen <andi@firstfloor.org>, Ben Maurer <bmaurer@fb.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Chris Lameter <cl@linux.com>, Dave Watson <davejwatson@fb.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Joel Fernandes <joelaf@google.com>,
        Josh Triplett <josh@joshtriplett.org>,
        linux-api <linux-api@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-kselftest <linux-kselftest@vger.kernel.org>,
        Russell King <linux@arm.linux.org.uk>,
        Andy Lutomirski <luto@amacapital.net>,
        Ingo Molnar <mingo@redhat.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Paul <paulmck@linux.vnet.ibm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Paul Turner <pjt@google.com>, rostedt <rostedt@goodmis.org>,
        shuah <shuah@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        Will Deacon <will.deacon@arm.com>
Message-ID: <1813399266.597377.1579713392568.JavaMail.zimbra@efficios.com>
In-Reply-To: <CAODFU0rTLmb-Ph_n1EHaZmdOAjsa6Jmx=3zkuT8LH3No=sOk5w@mail.gmail.com>
References: <CAODFU0rTLmb-Ph_n1EHaZmdOAjsa6Jmx=3zkuT8LH3No=sOk5w@mail.gmail.com>
Subject: Re: [RFC PATCH v1] pin_on_cpu: Introduce thread CPU pinning system
 call
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Thread-Topic: pin_on_cpu: Introduce thread CPU pinning system call
Thread-Index: dvBLZ91ySDgPt1Gh4255dg7wp2uMvw==
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

(replying again as plain text for mailing lists)

----- On Jan 22, 2020, at 10:44 AM, Jan Ziak 0xe2.0x9a.0x9b@gmail.com wrote:

> Hello

> I would like to note that this does not help userspace to express dynamic
> scheduling relationships among processes/threads such as "do not run processes
> A and B on the same core" or "run processes A and B on cores sharing the same
> L2 cache".

Indeed, this is not what this system call is trying to solve. Does the name "pin_on_cpu" lead 
to confusion here ? 

I thought that cgroups was already the mechanism taking care of this kind of requirement. 

Thanks, 

Mathieu 

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com