At least KVM in Proxmox seems not happy about it. Just to be safe
block it for all VMs, since it should just improve profile accuracy.
MFC after: 1 week
With clang 15, the following -Werror warning is produced:
sys/dev/hwpmc/hwpmc_arm64.c:530:21: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
pmc_arm64_initialize()
^
void
This is because many of the functions are declared with a (void)
argument list, but defined with an empty argument list. Make the
definition match the declaration.
Sponsored by: The FreeBSD Foundation
Make most AST handlers dynamically registered. This allows to have
subsystem-specific handler source located in the subsystem files,
instead of making subr_trap.c aware of it. For instance, signal
delivery code on return to userspace is now moved to kern_sig.c.
Also, it allows to have some handlers designated as the cleanup (kclear)
type, which are called both at AST and on thread/process exit. For
instance, ast(), exit1(), and NFS server no longer need to be aware
about UFS softdep processing.
The dynamic registration also allows third-party modules to register AST
handlers if needed. There is one caveat with loadable modules: the
code does not make any effort to ensure that the module is not unloaded
before all threads processed through AST handler in it. In fact, this
is already present behavior for hwpmc.ko and ufs.ko. I do not think it
is worth the efforts and the runtime overhead to try to fix it.
Reviewed by: markj
Tested by: emaste (arm64), pho
Discussed with: jhb
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D35888
With clang 15, the following -Werror warnings are produced:
sys/dev/hwpmc/hwpmc_mod.c:4805:6: error: variable 'nfree' set but not used [-Werror,-Wunused-but-set-variable]
int nfree;
^
sys/dev/hwpmc/hwpmc_mod.c:4804:6: error: variable 'ncallchains' set but not used [-Werror,-Wunused-but-set-variable]
int ncallchains;
^
The 'nfree' and 'ncallchains' variables were used in KASSERTs, but these
were removed due to refactoring in d9f1b8dbf2. Remove the variables
since they no longer serve any purpose.
MFC after: 3 days
With clang 15, the following -Werror warning is produced:
sys/dev/hwpmc/hwpmc_mod.c:2462:33: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
pmc_thread_descriptor_pool_drain()
^
void
This is because pmc_thread_descriptor_pool_drain() is declared with a
(void) argument list, but defined with an empty argument list. Make the
definition match the declaration.
MFC after: 3 days
With clang 15, the following -Werror warning is produced:
sys/dev/hwpmc/hwpmc_x86.c:245:18: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
pcm_md_initialize()
^
void
This is because pcm_md_initialize() is declared with a (void) argument
list, but defined with an empty argument list. Make the definition match
the declaration.
MFC after: 3 days
With clang 15, the following -Werror warnings are produced:
sys/dev/hwpmc/hwpmc_logging.c:1228:18: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
pmclog_initialize()
^
void
sys/dev/hwpmc/hwpmc_logging.c:1277:16: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
pmclog_shutdown()
^
void
This is because pcmlog_{initialize,shutdown}() are declared with (void)
argument lists, but defined with empty argument lists. Make the
definitions match the declarations.
MFC after: 3 days
Fix builds after 1459a22787 and
59191f3573 by using __diagused
for variables only used in KASSERT().
In addition remove two debug lines that look like a copy and paste error
from dmc620 to cmn600.
Further add the newly introduced files to sys/confg/files.arm64 as well
so that LINT compiles without missing symbols.
Fix build after e3572eb654 as
struct pmc_md_dmc620_pmu_op_pmcallocate is needed when building
libpmc/pmclog.c as it is partof the public API via machine/pmc_mdep.h.
Add support of ARM CMN-600 controller, PMU access functions only.
Add support of PMU counters of ARM CMN-600 controller.
Reviewed by: mhorne
Sponsored By: ARM
Differential Revision: https://reviews.freebsd.org/D32321
Doing otherwise may lead to lost interrupts, that in combination
with hardware PMCs freezing may leave them frozen forever. It may
also slightly improve profiling accuracy.
MFC after: 2 weeks
A rarely occurring event (e.g. an event that occurs less than 1000
times during execution of a program) may require a lower minimum
threshold than 1000. Replace the hardcoded 1000 with a sysctl that
the administrator can use to permit smaller sampling count values.
Reviewed by: mhorne, mav
Sponsored by: University of Cambridge, Google, Inc.
Differential Revision: https://reviews.freebsd.org/D35400
This allows to profile already running high-priority threads, that
otherwise by blocking thread migration to respective CPUs blocked PMC
management, i.e. profiling could start only when workload completed.
While there, return the thread to its original CPU after iterating
the list. Otherwise all threads using PMC end up on the last CPU.
MFC after: 1 month
After we wipe PMC configuration, including its local enable bit(s),
we don't really care about its global enable bit. Global enable bits
now may only be cleared by interrupt handler in case of error (sample
buffer overflow). Being set is actually a reset default for them.
This saves one WRMSR per process-scope PMC per context switch, that
is clearly visible in profiles.
MFC after: 1 month
The PMC subsystem is not designed for non-uniform CPU capabilities
(P/E-cores are different), but at least several working architectural
events like cpu_clk_unhalted.thread_p should be better than nothing.
MFC after: 1 month
Intel json's use event=0 to specify fixed counter number via umask.
Alternatively fixed counters have equivalent programmable event/umask.
MFC after: 1 month
Since version 2 Intel CPUs can freeze PMCs when intering PMI to reduce
PMI effects on collected statistics. Since version 4 hardware supports
"streamlined" mechanism, not requiring IA_GLOBAL_CTRL MSR access.
MFC after: 1 month
Support the "usr" and "os" qualifiers on arm64 events to restrict
event counting to either usermode or the kernel, respectively. If
neither qualifier is given, events are counted in both.
Reviewed by: emaste
Sponsored by: University of Cambridge, Google, Inc.
Differential Revision: https://reviews.freebsd.org/D34527
If a counter more than overflows just as we read it on switch out then,
if using sampling mode, we will negate this small value to give a huge
reload count, and if we later switch back in that context we will
validate that value against pm_reloadcount and panic an INVARIANTS
kernel with:
panic: [pmc,1470] pmcval outside of expected range cpu=2 ri=16 pmcval=fffff292 pm_reloadcount=10000
or similar. Presumably in a non-INVARIANTS kernel we will instead just
use the provided value as the reload count, which would lead to the
overflow not happing for a very long time (e.g. 78 minutes for a 48-bit
counter incrementing at an averate rate of 1GHz).
Instead, clamp the reload count to 0 (which corresponds precisely to the
value we would compute if it had just overflowed and no more), which
will result in hwpmc using the full original reload count again. This is
the approach used by core for Intel (for both fixed and programmable
counters).
As part of this, armv7 and arm64 are made conceptually simpler; rather
than skipping modifying the overflow count for sampling mode counters so
it's always kept as ~0, those special cases are removed so it's always
applicable and the concatentation of it and the hardware counter can
always be viewed as a 64-bit counter, which also makes them look more
like other architectures.
Whilst here, fix an instance of UB (shifting a 1 into the sign bit) for
amd in its sign-extension code.
Reviewed by: andrew, mhorne, kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D33654
Performance counters and overflow interrupts are assumed to be disabled
by default, but this is not guaranteed. Ensure we disable both during
per-cpu initialization, before enabling the PMU. Otherwise, some systems
(such as the Ampere eMAG) would experience an interrupt storm upon
loading the hwpmc module.
Reviewed by: br
MFC after: 5 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32854
Looking for "tsc-tsc" in the pmu tables will fail every time. Instead,
make this an alias for the static TSC event defined in pmc_events.h.
This fixes 'pmcstat -s cycles' on Intel and AMD.
Reviewed by: emaste
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32197
These checks were inconsistently applied across the various hwpmc
classes. The condition is already checked by the generic code in
hwpmc_mod.c, so remove them.
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31388
It is always a good idea. In one case, attempting to allocate N+1 PMCs
from a class with N hardware counters would incorrectly attempt to
allocate from the next class in the list. Without this validation, this
can lead to all kinds of strange behaviour.
Since powerpc_allocate_pmc() is used by both the mpc7xxx and ppc970
classes, add a new global to track which is active (it will never be
both).
Reviewed by: luporl, ray
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31387
