Snapdragon 820 L1d cache size

pytorch / cpuinfo

CPU INFOrmation library (x86/x86-64/ARM/ARM64, Linux/Windows/Android/macOS/iOS)

BSD 2-Clause "Simplified" License

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Snapdragon 820 L1d cache size #8

Closed psiha closed 6 years ago

psiha commented 6 years ago

arm/cache.c sets l1d.size = 24kB for the said uarch which is a bit weird/non-power-of-2 size for a data cache plus it does not correspond to the value of 32kB specified in the first link ([1] http://www.anandtech.com/show/9837/snapdragon-820-preview/2) ...

Maratyszcza commented 6 years ago

There is no bug in cpuinfo here, the table from Anandtech is wrong

psiha commented 6 years ago

Do you have a more authoritative source? This also suggests a 32kB L1d cache http://www.cs.man.ac.uk/~nobren/files/NunoNobre_TasterProjectReport.pdf ...

Maratyszcza commented 6 years ago

Some Snapdragon 820/821 devices have cache leaf in sysfs, and they report parameters as in cpuinfo.

psiha commented 6 years ago

Interesting, thanks for the answer...adding this comment to the source as well will at least prevent future tickets :) ...and so utterly strange the Qualcomm does not simply provide such basic information about their hardware...