Re: [PATCH v2 00/17] x86/resctrl : Support AMD Assignable Bandwidth Monitoring Counters (ABMC)

[Moger, Babu]

Hi Peter,

I want to get your feedback on this approach before I start working on 
it.  Please look at few examples below.

Thanks

Babu

On 3/4/2024 4:24 PM, Moger, Babu wrote:
> Hi Reinette,
>
> On 3/4/2024 1:58 PM, Reinette Chatre wrote:
> > Hi Babu,
> >
> > On 3/4/2024 11:34 AM, Moger, Babu wrote:
> > > On 3/1/2024 5:20 PM, Reinette Chatre wrote:
> > > > On 3/1/2024 12:36 PM, Moger, Babu wrote:
> > > > > On 2/29/24 15:50, Reinette Chatre wrote:
> > > > > > On 2/29/2024 12:37 PM, Moger, Babu wrote:
> > > > > To assign a counters to default group on domain 0.
> > > > > $echo "//00=+lt;01=+lt" > 
> > > > > /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> > > > It should not be necessary to use both "=" and "+" in the same 
> > > > assignment.
> > > > I think of "=" as "assign" and "+" as append ("-" as remove).
> > > Here are our options.
> > >
> > > a. assign one event (+)
> > I prefer that we use consistent interface with what users may be used to
> > in other kernel interfaces, like dynamic debug.
> > Considering that, "+" will not be "assign one event" but instead
> > (let me copy text from dynamic debug to help):
> > "+    add the given flags"
> >
> > So + will add (append) the provided flags to the matching domain, it
> > can be multiple flags and does not impact existing flags.
>
> ok. Sure.
>
>
> > > b. unassign one event (-)
> > "-    remove the given flags" - it can be multiple flags that should be
> > removed from domain.
> >
> > > c. assign both (++ may be?)
> > No. Please do not constrain the interface with what needs to be 
> > supported
> > for ABMC. We may want to add other flags in the future, do not limit 
> > it to
> > two flags.
> ok Sure.
> > > d. unassign both (_)
> > "=_" will unassign all flags without consideration of which flags
> > are set. User can also use "-l" to just unassign local MBM, "-t" to
> > unassign total MBM, or "-lt" to unassign local and total MBM 
> > specifically.
>
> oh ok. got it.
>
>
> > > I think append ( "=") is not required while assigning.  It is 
> > > confusing.
> > "=" is not append. It is assign:
> >
> > " =    set the flags to the given flags"
> ok.
> > > Assign or Add both involve same action.
> > >
> > > How about this? This might be easy to parse. May be space (" ") 
> > > after the domain id.
> > Why a space?
> >
> > > <group>/<domain id> <action><event>; <domain id> <action><event>
> > <control group>/<monitor group/<domain id><action><flags or 
> > _>;<domain id><action><flags or _>
>
>
> Based on our discussion, I am listing few examples here. Let me know 
> if I missed something.
>
>   mount  -t resctrl resctrl /sys/fs/resctrl/
>
> 1. Assign both local and total counters to default group on domain 0 
> and 1.
>    $echo "//00=lt;01=lt" > /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>
>    $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>    //00=lt;01=lt
>
> 2. Assign a total event to mon group inside the default group for both 
> domain 0 and 1.
>
>    $mkdir /sys/fs/resctrl/mon_groups/mon_a
>    $echo "/mon_a/00+t;01+t" > 
> /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>
>    $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>    //00=lt;01=lt
>    /mon_a/00=t;01=t
>
> 3. Assign a local event to non-default control mon group both domain 0 
> and 1.
>    $mkdir /sys/fs/resctrl/ctrl_a
>    $echo "/ctrl_a/00=l;01=l"  > 
> /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>
>    $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>    //00=lt;01=lt
>    /mon_a/00=t;01=t
>    /ctrl_a/00=l;01=l
>
> 4. Assign a both counters to mon group inside another control 
> group(non-default).
>    $mkdir /sys/fs/resctrl/ctrl_a/mon_ab/
>    $echo "ctrl_a/mon_ab/00=lt;01=lt" > 
> /sys/fs/resctrl/nfo/L3_MON/mbm_assign_contro
>
>    $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>    //00=lt;01=lt
>    /mon_a/00=t;01=t
>    /ctrl_a/00=l;01=l
>    ctrl_a/mon_ab/00=lt;01=lt
>
> 5. Unassign a counter to mon group inside another control 
> group(non-default).
>    $echo "ctrl_a/mon_ab/00-l;01-l" > 
> /sys/fs/resctrl/nfo/L3_MON/mbm_assign_control
>
>   $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>   //00=lt;01=lt
>   /mon_a/00=t;01=t
>   /ctrl_a/00=l;01=l
>   ctrl_a/mon_ab/00=t;01=t
>
> 6. Unassign all the counters on a specific group.
>    $echo "ctrl_a/mon_ab/00=_" > 
> /sys/fs/resctrl/nfo/L3_MON/mbm_assign_control
>
>    $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>    //00=lt;01=lt
>    /mon_a/00=t;01=t
>    /ctrl_a/00=l;01=l
>    ctrl_a/mon_ab/00=_;01=_
>
> Thanks
> Babu Moger