From 0102c8c7fdfc4bd700971daff2b94470f4eafae4 Mon Sep 17 00:00:00 2001 From: Dapeng Mi Date: Thu, 17 Sep 2026 09:52:33 +0800 Subject: perf/x86/intel: Rename DMR offcore_rsp attribute to offmodule_rsp DMR introduces Offmodule Response events in place of the legacy Offcore Response events, but it still exposes the inherited offcore_rsp PMU attribute for programming the corresponding MSR data. Rename the DMR PMU attribute to offmodule_rsp so the sysfs interface matches the underlying event name and avoids user & tooling confusion. Signed-off-by: Dapeng Mi Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://patch.msgid.link/20260917015234.981153-12-dapeng1.mi@linux.intel.com --- .../admin-guide/device-mapper/dm-flakey.rst | 88 ++++++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 Documentation/admin-guide/device-mapper/dm-flakey.rst (limited to 'Documentation/admin-guide/device-mapper/dm-flakey.rst') diff --git a/Documentation/admin-guide/device-mapper/dm-flakey.rst b/Documentation/admin-guide/device-mapper/dm-flakey.rst new file mode 100644 index 000000000..f967c5fea --- /dev/null +++ b/Documentation/admin-guide/device-mapper/dm-flakey.rst @@ -0,0 +1,88 @@ +========= +dm-flakey +========= + +This target is the same as the linear target except that it exhibits +unreliable behaviour periodically. It's been found useful in simulating +failing devices for testing purposes. + +Starting from the time the table is loaded, the device is available for + seconds, then exhibits unreliable behaviour for seconds, and then this cycle repeats. + +Also, consider using this in combination with the dm-delay target too, +which can delay reads and writes and/or send them to different +underlying devices. + +Table parameters +---------------- + +:: + + \ + [ []] + +Mandatory parameters: + + : + Full pathname to the underlying block-device, or a + "major:minor" device-number. + : + Starting sector within the device. + : + Number of seconds device is available. + : + Number of seconds device returns errors. + +Optional feature parameters: + + If no feature parameters are present, during the periods of + unreliability, all I/O returns errors. + + error_reads: + All read I/O is failed with an error signalled. + Write I/O is handled correctly. + + drop_writes: + All write I/O is silently ignored. + Read I/O is handled correctly. + + error_writes: + All write I/O is failed with an error signalled. + Read I/O is handled correctly. + + corrupt_bio_byte : + During , replace of the data of + each matching bio with . + + : + The offset of the byte to replace. + Counting starts at 1, to replace the first byte. + : + Either 'r' to corrupt reads or 'w' to corrupt writes. + 'w' is incompatible with drop_writes. + : + The value (from 0-255) to write. + : + Perform the replacement only if bio->bi_opf has all the + selected flags set. + + random_read_corrupt + During , replace random byte in a read bio + with a random value. probability is an integer between + 0 and 1000000000 meaning 0% to 100% probability of corruption. + + random_write_corrupt + During , replace random byte in a write bio + with a random value. probability is an integer between + 0 and 1000000000 meaning 0% to 100% probability of corruption. + +Examples: + +Replaces the 32nd byte of READ bios with the value 1:: + + corrupt_bio_byte 32 r 1 0 + +Replaces the 224th byte of REQ_META (=32) bios with the value 0:: + + corrupt_bio_byte 224 w 0 32 -- cgit v1.3.1