+Cc Alexander. On 2019/5/8 1:58, Jeremy Linton wrote: > Hi, > > On 5/4/19 6:06 AM, Hanjun Guo wrote: >> Hi Jeremy, Mark, >> >> On 2019/5/4 7:24, Jeremy Linton wrote: >>> This patch series enables the Arm Statistical Profiling >>> Extension (SPE) on ACPI platforms. >>> >>> This is possible because ACPI 6.3 uses a previously >>> reserved field in the MADT to store the SPE interrupt >>> number, similarly to how the normal PMU is described. >>> If a consistent valid interrupt exists across all the >>> cores in the system, a platform device is registered. >>> That then triggers the SPE module, which runs as normal. >>> >>> We also add the ability to parse the PPTT for IDENTICAL >>> cores. We then use this to sanity check the single SPE >>> device we create. This creates a bit of a problem with >>> respect to the specification though. The specification >>> says that its legal for multiple tree's to exist in the >>> PPTT. We handle this fine, but what happens in the >>> case of multiple tree's is that the lack of a common >>> node with IDENTICAL set forces us to assume that there >>> are multiple non-IDENTICAL cores in the machine. >> >> Adding this patch set on top of latest mainline kernel, >> and tested on D06 which has the SPE feature, in boot message >> shows it was probed successfully: >> >> arm_spe_pmu arm,spe-v1: probed for CPUs 0-95 [max_record_sz 128, align 4, features 0x7] >> >> but when I test it with spe events such as >> >> perf record -c 1024 -e arm_spe_0/branch_filter=0/ -o spe ls >> >> it fails with: >> failed to mmap with 12 (Cannot allocate memory), >> >> Confirmed that patch [0] is merged and other perf events are working >> fine. > > Its pretty easy to get into the weeds with this driver, does it work with examples like: > > https://lkml.org/lkml/2018/1/14/122 No, not work at all. SPE works on 5.0, but not work after 5.1-rc1, bisected to this commit: 5768402fd9c6 perf/ring_buffer: Use high order allocations for AUX buffers optimistically Cced Alexander as well as Alexander is the author of above patch. Thanks Hanjun
