From c344436319e898784febbeeea71d1b0f65ef53ae Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Sat, 5 Sep 2009 05:10:15 -0300 Subject: Documentation/edac.txt: Improve it to reflect the latest changes at the driver Signed-off-by: Mauro Carvalho Chehab --- Documentation/edac.txt | 72 +++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 56 insertions(+), 16 deletions(-) (limited to 'Documentation/edac.txt') diff --git a/Documentation/edac.txt b/Documentation/edac.txt index 8bc320467c64..bd3f8a3905af 100644 --- a/Documentation/edac.txt +++ b/Documentation/edac.txt @@ -730,25 +730,41 @@ Due to the way Nehalem exports Memory Controller data, some adjustments were done at i7core_edac driver. This chapter will cover those differences 1) On Nehalem, there are one Memory Controller per Quick Patch Interconnect - (QPI). At the driver, the term "socket" means one QPI. It should also be - associated with the CPU physical socket. + (QPI). At the driver, the term "socket" means one QPI. This is + associated with a physical CPU socket. Each MC have 3 physical read channels, 3 physical write channels and 3 logic channels. The driver currenty sees it as just 3 channels. Each channel can have up to 3 DIMMs. The minimum known unity is DIMMs. There are no information about csrows. - As EDAC API maps the minimum unity is csrows, the driver exports one + As EDAC API maps the minimum unity is csrows, the driver sequencially + maps channel/dimm into different csrows. + + For example, suposing the following layout: + Ch0 phy rd0, wr0 (0x063f4031): 2 ranks, UDIMMs + dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400 + dimm 1 1024 Mb offset: 4, bank: 8, rank: 1, row: 0x4000, col: 0x400 + Ch1 phy rd1, wr1 (0x063f4031): 2 ranks, UDIMMs + dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400 + Ch2 phy rd3, wr3 (0x063f4031): 2 ranks, UDIMMs + dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400 + The driver will map it as: + csrow0: channel 0, dimm0 + csrow1: channel 0, dimm1 + csrow2: channel 1, dimm0 + csrow3: channel 2, dimm0 + +exports one DIMM per csrow. - Currently, it also exports the several memory controllers as just one. This - limit will be removed on future versions of the driver. + Each QPI is exported as a different memory controller. 2) Nehalem MC has the hability to generate errors. The driver implements this functionality via some error injection nodes: For injecting a memory error, there are some sysfs nodes, under - /sys/devices/system/edac/mc/mc0/: + /sys/devices/system/edac/mc/mc?/: inject_addrmatch: Controls the error injection mask register. It is possible to specify @@ -779,11 +795,6 @@ were done at i7core_edac driver. This chapter will cover those differences 2 for the highest 1 for the lowest - inject_socket: - specifies what QPI (or processor socket) will generate the error. - on Xeon 35xx, it should be 0. - on Xeon 55xx, it should be 0 or 1. - inject_type: specifies the type of error, being a combination of the following bits: bit 0 - repeat @@ -806,10 +817,12 @@ were done at i7core_edac driver. This chapter will cover those differences echo 2 >/sys/devices/system/edac/mc/mc0/inject_type echo 64 >/sys/devices/system/edac/mc/mc0/inject_eccmask echo 3 >/sys/devices/system/edac/mc/mc0/inject_section - echo 0 >/sys/devices/system/edac/mc/mc0/inject_socket echo 1 >/sys/devices/system/edac/mc/mc0/inject_enable dd if=/dev/mem of=/dev/null seek=16k bs=4k count=1 >& /dev/null + For socket 1, it is needed to replace "mc0" by "mc1" at the above + commands. + The generated error message will look like: EDAC MC0: UE row 0, channel-a= 0 channel-b= 0 labels "-": NON_FATAL (addr = 0x0075b980, socket=0, Dimm=0, Channel=2, syndrome=0x00000040, count=1, Err=8c0000400001009f:4000080482 (read error: read ECC error)) @@ -821,9 +834,36 @@ were done at i7core_edac driver. This chapter will cover those differences separate sysfs note were created to handle such counters. They can be read by looking at the contents of "corrected_error_counts" - counter: + counter. Due to hardware limits, the output is different on machines + with unregistered memories and machines with registered ones. + + With unregistered memories, it outputs: $ cat /sys/devices/system/edac/mc/mc0/corrected_error_counts - dimm0: 15866 - dimm1: 0 - dimm2: 27285 + all channels UDIMM0: 0 UDIMM1: 0 UDIMM2: 0 + + What happens here is that errors on different csrows, but at the same + dimm number will increment the same counter. + So, in this memory mapping: + csrow0: channel 0, dimm0 + csrow1: channel 0, dimm1 + csrow2: channel 1, dimm0 + csrow3: channel 2, dimm0 + The hardware will increment UDIMM0 for an error at either csrow0, csrow2 + or csrow3. + + With registered memories, it outputs: + + $cat /sys/devices/system/edac/mc/mc0/corrected_error_counts + channel 0 RDIMM0: 0 RDIMM1: 0 RDIMM2: 0 + channel 1 RDIMM0: 0 RDIMM1: 0 RDIMM2: 0 + channel 2 RDIMM0: 0 RDIMM1: 0 RDIMM2: 0 + + So, with registered memories, there's a direct map between a csrow and a + counter. + +4) Standard error counters + + The standard error counters are generated when an mcelog error is received + by the driver. Since it is counted by software, it is possible that some + errors could be lost. -- cgit v1.2.3