Messages in this thread | | | Date | Tue, 24 Nov 2015 16:27:54 +0800 | From | Chao Peng <> | Subject | Re: [RFD] CAT user space interface revisited |
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On Wed, Nov 18, 2015 at 10:01:54PM -0200, Marcelo Tosatti wrote: > > tglx > > Again: you don't need to look into the MSR table and relate it > to tasks if you store the data as: > > task group 1 = { > reservation-1 = {size = 80Kb, type = data, socketmask = 0xffff}, > reservation-2 = {size = 100Kb, type = code, socketmask = 0xffff} > } > > task group 2 = { > reservation-1 = {size = 80Kb, type = data, socketmask = 0xffff}, > reservation-3 = {size = 200Kb, type = code, socketmask = 0xffff} > } > > Task group 1 and task group 2 share reservation-1.
Because there is only size but not CBM position info, I guess for different reservations they will not overlap each other, right?
Personally I like this way of exposing minimal information to userspace. I can think it working well except for one concern of losing flexibility:
For instance, there is a box for which the full CBM is 0xfffff. After cache reservation creating/freeing for a while we then have reservations:
reservation1: 0xf0000 reservation2: 0x00ff0
Now people want to request a reservation which size is 0xff, so how will kernel do at this time? It could return just error or do some moving/merging (e.g. for reservation2: 0x00ff0 => 0x0ff00) and then satisfy the request. But I don't know if the moving/merging will cause delay for tasks that is using it.
Thanks, Chao
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