Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
It is possible that wrmsr in amd_stop_pmc() causes an overflow in a counter
that it disables. In that case a non-maskable interrupt is generated. The
interrupt handler code was written in such a way that it would re-enable the
counter. That would lead to an unexpected interrupt later on.
This problem was easy to reproduce with
$ pmcstat -T -P instructions -t $pid
if the target process is sufficiently busy and there are context switches from
time to time. There would be a lot of interrupts to "race" with amd_stop_pmc()
called during the context switches. The problem affected only AMD processors.
While there, trace whether amd_intr() claimed an interrupt.
Reviewed by: jhb
MFC after: 2 weeks
New kernel events can be added at various location for sampling or counting.
This will for example allow easy system profiling whatever the processor is
with known tools like pmcstat(8).
Simultaneous usage of software PMC and hardware PMC is possible, for example
looking at the lock acquire failure, page fault while sampling on
instructions.
Sponsored by: NETASQ
MFC after: 1 month
hardware for PMCs that have been configured for sampling.
- Bug fix: acknowledge PMC hardware overflows irrespective of the
the (software) PMC's state.
dependencies. A 'struct pmc_classdep' structure describes operations
on PMCs; 'struct pmc_mdep' contains one or more 'struct pmc_classdep'
structures depending on the CPU in question.
Inside PMC class dependent code, row indices are relative to the
PMCs supported by the PMC class; MI code in "hwpmc_mod.c" translates
global row indices before invoking class dependent operations.
- Augment the OP_GETCPUINFO request with the number of PMCs present
in a PMC class.
- Move code common to Intel CPUs to file "hwpmc_intel.c".
- Move TSC handling to file "hwpmc_tsc.c".
2's compliment.
The 2's compliment transform is done so a "count down" sampling interval
can be converted into a "count up" PMC value. a 2's complimented 'count down'
value is written to the PMC counter; then the read-back counter is reverted
via another 2's compliment.
PR: kern/121660
Reviewed by: jkoshy
Approved by: jkoshy
MFC after: 1 week
'buffers' pending NMIs from multiple interrupting PMCs and delivers
them serially.
Reported by: Olivier Crameri <olivier.crameri@epfl.ch>
MFC after: 3 days
- Update driver interrupt statistics correctly.
sys/sys/pmc.h, sys/dev/hwpmc/hwpmc_mod.c:
- Fix a bug affecting debug printfs.
- Move the 'stalled' flag from being in a bit in the
'pm_flags' field of a 'struct pmc' to a field of its own in the
same structure. This flag is updated from the NMI handler and
keeping it separate makes it easier to avoid races with other
parts of the code.
sys/dev/hwpmc/hwpmc_logging.c:
- Do arithmetic with 'uintptr_t' types rather that casting
to and from 'char *'.
Approved by: re (scottl)
- Implement sampling modes and logging support in hwpmc(4).
- Separate MI and MD parts of hwpmc(4) and allow sharing of
PMC implementations across different architectures.
Add support for P4 (EMT64) style PMCs to the amd64 code.
- New pmcstat(8) options: -E (exit time counts) -W (counts
every context switch), -R (print log file).
- pmc(3) API changes, improve our ability to keep ABI compatibility
in the future. Add more 'alias' names for commonly used events.
- bug fixes & documentation.
Have pmcstat(8) and pmccontrol(8) use these APIs.
Return PMC class-related constants (PMC widths and capabilities)
with the OP GETCPUINFO call leaving OP PMCINFO to return only the
dynamic information associated with a PMC (i.e., whether enabled,
owner pid, reload count etc.).
Allow pmc_read() (i.e., OPS PMCRW) on active self-attached PMCs to
get upto-date values from hardware since we can guarantee that the
hardware is running the correct PMC at the time of the call.
Bug fixes:
- (x86 class processors) Fix a bug that prevented an RDPMC
instruction from being recognized as permitted till after the
attached process had context switched out and back in again after
a pmc_start() call.
Tighten the rules for using RDPMC class instructions: a GETMSR
OP is now allowed only after an OP ATTACH has been done by the
PMC's owner to itself. OP GETMSR is not allowed for PMCs that
track descendants, for PMCs attached to processes other than
their owner processes.
- (P4/HTT processors only) Fix a bug that caused the MI and MD
layers to get out of sync. Add a new MD operation 'get_config()'
as part of this fix.
- Allow multiple system-mode PMCs at the same row-index but on
different CPUs to be allocated.
- Reject allocation of an administratively disabled PMC.
Misc. code cleanups and refactoring. Improve a few comments.
Only allow a process to use the x86 RDPMC instruction if it has
allocated and attached a PMC to itself.
Inform the MD layer of the "pseudo context switch out" that needs
to be done when the last thread of a process is exiting.
includes the MD header for us. Do not include <machine/specialreg.h>
as it is not a header file that can be included from MI files. It
is included from <machine/pmc_mdep.h> if so needed and possible.
Ok'd: jkoshy@
