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Update README to include the new error reporting modes.

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Martin Whitaker 2024-11-09 18:24:02 +00:00
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README.md
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@ -274,6 +274,8 @@ The configuration menu allows the user to:
* error summary
* individual errors
* BadRAM patterns
* Linux memmap
* bad pages
* select which of the available CPU cores are used (at startup only)
* a maximum of 256 CPU cores can be selected, due to memory and
display limits
@ -291,7 +293,9 @@ The error reporting mode may be changed at any time without disrupting the
current test sequence. Error statistics are collected regardless of the
current error reporting mode (so switching to error summary mode will show
the accumulated statistics since the current test sequence started). BadRAM
patterns are only accumulated when in BadRAM mode.
patterns are only accumulated when in BadRAM mode. Linux memmap regions are
only accumulated when in memmap mode. Bad page numbers are only accumulated
when in bad page mode.
Any change to the selected tests, address range, or CPU sequencing mode will
start a new test sequence and reset the error statistics.
@ -343,17 +347,18 @@ instance:
### BadRAM Patterns
The BadRAM patterns mode accumulates and displays error patterns for use with
the [Linux BadRAM feature](http://rick.vanrein.org/linux/badram/). Lines are
printed in the form `badram=F1,M1,F2,M2...` In each `F,M` pair, the `F`
represents a fault address and the `M` is a bitmask for that address. These
the [Linux BadRAM feature](http://rick.vanrein.org/linux/badram/) or [GRUB
badram command](https://www.gnu.org/software/grub/manual/grub/grub.html#badram).
Lines are printed in the form `badram=F1,M1,F2,M2...` In each `F,M` pair, the
`F` represents a fault address and the `M` is a bitmask for that address. These
patterns state that faults have occurred in addresses that equal F on all `1`
bits in M. Such a pattern may capture more errors that actually exist, but
bits in M. Such a pattern may capture more errors than actually exist, but
at least all the errors are captured. These patterns have been designed to
capture regular patterns of errors caused by the hardware structure in a terse
syntax.
The BadRAM patterns are grown incrementally rather than calculated from an
overview of all errors. The number of pairs is constrained to ten for a
overview of all errors. The number of pairs is constrained to 20 for a
number of practical reasons. As a result, handcrafting patterns from the
output in address printing mode may, in exceptional cases, yield better
results.
@ -363,6 +368,39 @@ address test (test 0) and the block move test (test 7) do not contribute to
the BadRAM patterns as these tests do not allow the exact address of the
fault to be determined.
### Linux memmap
The Linux memmap mode accumulates and displays faulty memory regions for use
with the [Linux memmap boot command line option]
(https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt).
Lines are printed in the form `memmap=S1$A1,S2,A2...` In each `S,A` pair, the
`A` represents the first address in the region and the `S` is the size of the
region (in bytes). Up to 20 faulty memory regions are recorded. Once more than
20 regions of contiguous faulty locations have been found, regions will be
merged, which will mean some regions include non-faulty locations. The program
will try to minimise the number of non-faulty locations that are included.
**NOTE** As mentioned in the individual test descriptions, the walking-ones
address test (test 0) and the block move test (test 7) do not contribute to
the faulty memory regions as these tests do not allow the exact address of
the fault to be determined.
### Bad Pages
The bad pages mode accumulates and displays faulty memory page numbers. These
may be used with the Windows bcdedit command to add those pages to the Windows
PFA memory list. The page numbers are either displayed as a single hexadecimal
number (e.g. `0x20`) or a range of hexadecimal page numbers (e.g. `0x20..0x2a`).
Up to 20 ranges of faulty pages are recorded. Once more than 20 ranges of
contiguous faulty pages have been found, ranges will be merged, which will
mean some ranges include non-faulty pages. The program will try to minimise
the number of non-faulty pages that are included.
**NOTE** As mentioned in the individual test descriptions, the walking-ones
address test (test 0) and the block move test (test 7) do not contribute to
the faulty page numbers as these tests do not allow the exact address of the
fault to be determined.
## Trouble-shooting Memory Errors
Please be aware that not all errors reported by Memtest86+ are due to bad
@ -517,8 +555,8 @@ memory region in turn. Caching is enabled for all but the first test.
### Test 0 : Address test, walking ones, no cache
In each memory region in turn, tests all address bits by using a walking
ones address pattern. Errors from this test are not used to calculate BadRAM
patterns.
ones address pattern. Errors from this test do not contribute to BadRAM
patterns, memmap regions, or bad page regions.
### Test 1 : Address test, own address in window
@ -571,7 +609,7 @@ the movs instruction. After the moves are completed the data patterns are
checked. Because the data is checked only after the memory moves are completed
it is not possible to know where the error occurred. The addresses reported
are only for where the bad pattern was found. In consequence, errors from this
test are not used to calculate BadRAM patterns.
test do not contribute to BadRAM patterns, memmap regions, or bad page regions.
### Test 8 : Random number sequence