lkml.org 
[lkml]   [2018]   [Mar]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v7 00/13] Support PPTT for ARM64
From
Date
Hi,

First thanks for testing this!!

On 03/08/2018 09:59 AM, Ard Biesheuvel wrote:
> On 27 February 2018 at 18:49, Jeremy Linton <jeremy.linton@arm.com> wrote:
>> On 03/01/2018 06:06 AM, Sudeep Holla wrote:
>>>
>>> Hi Jeremy,
>>>
>>> On 28/02/18 22:06, Jeremy Linton wrote:
>>>>
>>>> ACPI 6.2 adds the Processor Properties Topology Table (PPTT), which is
>>>> used to describe the processor and cache topology. Ideally it is
>>>> used to extend/override information provided by the hardware, but
>>>> right now ARM64 is entirely dependent on firmware provided tables.
>>>>
>>>> This patch parses the table for the cache topology and CPU topology.
>>>> When we enable ACPI/PPTT for arm64 we map the physical_id to the
>>>> PPTT node flagged as the physical package by the firmware.
>>>> This results in topologies that match what the remainder of the
>>>> system expects. To avoid inverted scheduler domains we then
>>>> set the MC domain equal to the largest cache within the socket
>>>> below the NUMA domain.
>>>>
>>> I remember reviewing and acknowledging most of the cacheinfo stuff with
>>> couple of minor suggestions for v6. I don't see any Acked-by tags in
>>> this series and don't know if I need to review/ack any more cacheinfo
>>> related patches.
>>
>>
>> Hi,
>>
>> Yes, I didn't put them in because I changed the functionality in 2/13 and
>> there is a bug fix in 5/13. I thought you might want to do a quick diff of
>> the git v6->v7 tree.
>>
>> Although given that most of the changes were in response to your comments in
>> v6 I probably should have just put the tags in.
>>
>
> I get sane output from lstopo when applying these patches and booting
> my Socionext SynQuacer in ACPI mode:
>
> $ lstopo-no-graphics
> Machine (31GB)
> Package L#0 + L3 L#0 (4096KB)
> L2 L#0 (256KB)
> L1d L#0 (32KB) + L1i L#0 (32KB) + Core L#0 + PU L#0 (P#0)
> L1d L#1 (32KB) + L1i L#1 (32KB) + Core L#1 + PU L#1 (P#1)
> L2 L#1 (256KB)
> L1d L#2 (32KB) + L1i L#2 (32KB) + Core L#2 + PU L#2 (P#2)
> L1d L#3 (32KB) + L1i L#3 (32KB) + Core L#3 + PU L#3 (P#3)
> L2 L#2 (256KB)
> L1d L#4 (32KB) + L1i L#4 (32KB) + Core L#4 + PU L#4 (P#4)
> L1d L#5 (32KB) + L1i L#5 (32KB) + Core L#5 + PU L#5 (P#5)
> L2 L#3 (256KB)
> L1d L#6 (32KB) + L1i L#6 (32KB) + Core L#6 + PU L#6 (P#6)
> L1d L#7 (32KB) + L1i L#7 (32KB) + Core L#7 + PU L#7 (P#7)
> L2 L#4 (256KB)
> L1d L#8 (32KB) + L1i L#8 (32KB) + Core L#8 + PU L#8 (P#8)
> L1d L#9 (32KB) + L1i L#9 (32KB) + Core L#9 + PU L#9 (P#9)
> L2 L#5 (256KB)
> L1d L#10 (32KB) + L1i L#10 (32KB) + Core L#10 + PU L#10 (P#10)
> L1d L#11 (32KB) + L1i L#11 (32KB) + Core L#11 + PU L#11 (P#11)
> L2 L#6 (256KB)
> L1d L#12 (32KB) + L1i L#12 (32KB) + Core L#12 + PU L#12 (P#12)
> L1d L#13 (32KB) + L1i L#13 (32KB) + Core L#13 + PU L#13 (P#13)
> L2 L#7 (256KB)
> L1d L#14 (32KB) + L1i L#14 (32KB) + Core L#14 + PU L#14 (P#14)
> L1d L#15 (32KB) + L1i L#15 (32KB) + Core L#15 + PU L#15 (P#15)
> L2 L#8 (256KB)
> L1d L#16 (32KB) + L1i L#16 (32KB) + Core L#16 + PU L#16 (P#16)
> L1d L#17 (32KB) + L1i L#17 (32KB) + Core L#17 + PU L#17 (P#17)
> L2 L#9 (256KB)
> L1d L#18 (32KB) + L1i L#18 (32KB) + Core L#18 + PU L#18 (P#18)
> L1d L#19 (32KB) + L1i L#19 (32KB) + Core L#19 + PU L#19 (P#19)
> L2 L#10 (256KB)
> L1d L#20 (32KB) + L1i L#20 (32KB) + Core L#20 + PU L#20 (P#20)
> L1d L#21 (32KB) + L1i L#21 (32KB) + Core L#21 + PU L#21 (P#21)
> L2 L#11 (256KB)
> L1d L#22 (32KB) + L1i L#22 (32KB) + Core L#22 + PU L#22 (P#22)
> L1d L#23 (32KB) + L1i L#23 (32KB) + Core L#23 + PU L#23 (P#23)
> HostBridge L#0
> PCIBridge
> PCIBridge
> PCI 1b21:0612
> Block(Disk) L#0 "sda"
> HostBridge L#3
> PCI 10de:128b
> GPU L#1 "renderD128"
> GPU L#2 "card0"
> GPU L#3 "controlD64"
>
> So
>
> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>
> *However*, while hacking on the firmware that exposes the table, I
> noticed that a malformed structure (incorrect size) can get the parser
> in an infinite loop, hanging the boot after
>
> [ 8.244281] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
> [ 8.251780] Serial: AMBA driver
> [ 8.255042] msm_serial: driver initialized
> [ 8.259752] ACPI PPTT: Cache Setup ACPI cpu 0
> [ 8.264121] ACPI PPTT: Looking for data cache
> [ 8.268484] ACPI PPTT: Looking for CPU 0's level 1 cache type 0
>
> so I guess the parsing code could be made a bit more robust?
>

I've been wondering how long it would take for someone to complain about
one of these cases, I added a check in find_processor_node back a few
revisions ago to deal with zero length's causing infinite loops, but the
leaf node check doesn't have one, and that is likely what your hitting.

\
 
 \ /
  Last update: 2018-03-08 18:42    [W:0.057 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site