Could anybody tell me what is IO directory cache used for?
I am testing NVDIMM write system performance in our system like as below.
I created a source buffer in RDIMM which is attached to CPU 1.
Then the DMA engine in the PCIe switch which is attached to CPU 1 reads the source buffer and write it to the NVDIMM which is attached to CPU 0.
In above test, I found if the IO directory cache(IODC) option is "Enable for Remote InvItoM Hybrid AllocNonAlloc" in BIOS, we can get better write performance.
In contrast, if the IO directory cache(IODC) option is "Auto", the NVDIMM write performance is bad.
Does anyone can point me to relevant documentation or explain what is IO directory cache used for.
Thank you very much!