Intel E7-8891 v2 CM8063601377422 Manuel D’Utilisation

Intel

®

 Xeon

® 

Processor E7-2800/4800/8800 v2 Product Family

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Datasheet Volume Two: Functional Description, February 2014

The expectation is that a system cold reset must be performed when a fatal error/viral 
condition is detected.

This chapter describes the Intel Xeon processor E7 v2 product family memory 
RAS features. 

The memory controller implements several RAS features that provide increasing levels 
of reliability in exchange for certain system costs.

The iMC write buffers will store one parity bit per 64 data bits. Parity will be checked 
when the data is read out of the buffer to perform a write. 

Memory mirroring is the mechanism by which a component of memory is mirrored. In 
mirrored mode, typically, when a write is performed to one copy, a write is generated to 
the target location as well. This guarantees that the target is always updated with the 
latest data from the main copy.

There is one common hardware engine used for sparing and patrol scrubbing, so only 
one such operation can be performed at a time.

Demand scrubbing is the ability to write corrected data back to the memory once a 
correctable error is detected on a read transaction. This allows for correction of data in 
memory at detect, and decrease the chances of a second error on the same address 
accumulating to cause a multi-bit error condition.

Patrol scrubbing is accomplished using an engine that generates requests to memory 
addresses in a stride. The engine will generate a memory request at the pre-
programmed frequency, and the demand scrubbing flow corrects the error, if any. Patrol 
scrubbing finds opportunities on idle cycles to scrub the memory and get rid of any 
detectable correctable errors. 

Patrol scrubs are intended to ensure that data with a correctable error does not remain 
in DRAM long enough to stand a significant chance of further corruption to a 
uncorrectable error. 

Demand scrubbing is an insurance policy for when an error is encountered during a 
system read. Demand scrubbing in Intel Xeon processor E7 v2 product family is 
handled by the HA.