Re: Cache Allocation Technology Design

From: Peter Zijlstra <peterz@infradead.org>
To: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Matt Fleming <matt@console-pimps.org>,
	vikas <vikas.shivappa@linux.intel.com>,
	linux-kernel@vger.kernel.org,
	"matt.fleming" <matt.fleming@intel.com>,
	"will.auld" <will.auld@intel.com>,
	tj@kernel.org
Subject: Re: Cache Allocation Technology Design
Date: Wed, 29 Oct 2014 19:16:54 +0100	[thread overview]
Message-ID: <20141029181654.GR12706@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.10.1410291020020.26215@vshiva-Udesk>

On Wed, Oct 29, 2014 at 10:26:16AM -0700, Vikas Shivappa wrote:
> >It appears to me this 'mode' thing is entirely superfluous and can be
> >constructed by voluntary operation of this and cpusets or manual
> >affinity calls.
> 
> Do you mean user would would just user the cpusets for cpu affinity and CAT
> cgroup for cache allocation as shown in example below ?
> 
> In other words say affinitize the PID1 and PID2 to CPUs 1 and 2
>  and then set the desired cache allocation as well like below - then we have
> the desired cpu affinity and cache allocation for these PIDs..
> 
> cd /sys/fs/cgroup/cpuset
> 
> mkdir group1_specialuse
> /bin/echo 1-2 > cpuset.cpus
> /bin/echo PID1 > tasks
> /bin/echo PID2 > tasks
> 
> Now come to CAT and do the cache allocation for the same tasks PID1 and
> PID2.
> 
> cd /sys/fs/cgroup/cat (CAT cgroup)
> 
> mkdir group1_specialuse (keeping same name just for understanding)
> /bin/echo 0xf > cat.cbm (set the cache bit mask)
> /bin/echo PID1 > tasks
> /bin/echo PID2 > tasks
> 

Yah, except I have a strong urge to mount cpusets under /dog when you
put it like that ;-)

Or co-mount cpusets and pets and do it that way.