You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
83 lines
3.2 KiB
83 lines
3.2 KiB
|
|
Configurable sysfs parameters for the x86-64 machine check code. |
|
|
|
Machine checks report internal hardware error conditions detected |
|
by the CPU. Uncorrected errors typically cause a machine check |
|
(often with panic), corrected ones cause a machine check log entry. |
|
|
|
Machine checks are organized in banks (normally associated with |
|
a hardware subsystem) and subevents in a bank. The exact meaning |
|
of the banks and subevent is CPU specific. |
|
|
|
mcelog knows how to decode them. |
|
|
|
When you see the "Machine check errors logged" message in the system |
|
log then mcelog should run to collect and decode machine check entries |
|
from /dev/mcelog. Normally mcelog should be run regularly from a cronjob. |
|
|
|
Each CPU has a directory in /sys/devices/system/machinecheck/machinecheckN |
|
(N = CPU number) |
|
|
|
The directory contains some configurable entries: |
|
|
|
Entries: |
|
|
|
bankNctl |
|
(N bank number) |
|
64bit Hex bitmask enabling/disabling specific subevents for bank N |
|
When a bit in the bitmask is zero then the respective |
|
subevent will not be reported. |
|
By default all events are enabled. |
|
Note that BIOS maintain another mask to disable specific events |
|
per bank. This is not visible here |
|
|
|
The following entries appear for each CPU, but they are truly shared |
|
between all CPUs. |
|
|
|
check_interval |
|
How often to poll for corrected machine check errors, in seconds |
|
(Note output is hexademical). Default 5 minutes. When the poller |
|
finds MCEs it triggers an exponential speedup (poll more often) on |
|
the polling interval. When the poller stops finding MCEs, it |
|
triggers an exponential backoff (poll less often) on the polling |
|
interval. The check_interval variable is both the initial and |
|
maximum polling interval. 0 means no polling for corrected machine |
|
check errors (but some corrected errors might be still reported |
|
in other ways) |
|
|
|
tolerant |
|
Tolerance level. When a machine check exception occurs for a non |
|
corrected machine check the kernel can take different actions. |
|
Since machine check exceptions can happen any time it is sometimes |
|
risky for the kernel to kill a process because it defies |
|
normal kernel locking rules. The tolerance level configures |
|
how hard the kernel tries to recover even at some risk of |
|
deadlock. Higher tolerant values trade potentially better uptime |
|
with the risk of a crash or even corruption (for tolerant >= 3). |
|
|
|
0: always panic on uncorrected errors, log corrected errors |
|
1: panic or SIGBUS on uncorrected errors, log corrected errors |
|
2: SIGBUS or log uncorrected errors, log corrected errors |
|
3: never panic or SIGBUS, log all errors (for testing only) |
|
|
|
Default: 1 |
|
|
|
Note this only makes a difference if the CPU allows recovery |
|
from a machine check exception. Current x86 CPUs generally do not. |
|
|
|
trigger |
|
Program to run when a machine check event is detected. |
|
This is an alternative to running mcelog regularly from cron |
|
and allows to detect events faster. |
|
monarch_timeout |
|
How long to wait for the other CPUs to machine check too on a |
|
exception. 0 to disable waiting for other CPUs. |
|
Unit: us |
|
|
|
TBD document entries for AMD threshold interrupt configuration |
|
|
|
For more details about the x86 machine check architecture |
|
see the Intel and AMD architecture manuals from their developer websites. |
|
|
|
For more details about the architecture see |
|
see http://one.firstfloor.org/~andi/mce.pdf
|
|
|