AnsweredAssumed Answered

Can the iGPU of an APU access the CPUs' L2-cache?

Question asked by h_l on Jan 22, 2016
Latest reply on Apr 15, 2016 by h_l

Hi,

 

my questions are related to the caches of A10-78[5|7]0K APUs.

  1. I wonder if the iGPU can directly access data from a L2-cache of a CPU module?
  2. Are the two L2-caches shared among the two CPU modules?

 

Thanks!

 

----

Regarding 1)

The slides from HOT CHIPS [1] are not very clear and the discussion in [2] says, that the iGPUs' L2 is of size 512KB whereas the CPU has 2x2MB. This would imply that either GPU and CPU don't share the L2 cache or that the CPU-L2 is the "L3" of the GPU.

In the work of He et al. [3], the CPU is used to prefetch data into L2 which results into ~30% less memory stalls on the GPU.

 

[1] http://www.hotchips.org/wp-content/uploads/hc_archives/hc26/HC26-11-day1-epub/HC26.11-2-Mobile-Processors-epub/HC26.11.2…

[2] What is the Size of GPU L2 cache for A10-7850k APU?

[3] http://www.vldb.org/pvldb/vol8/p329-he.pdf

Outcomes