Right now, userspace (fast) gettimeofday(2) on x86 only works for
RDTSC. For older machines, like Core2, where RDTSC is not C2/C3
invariant, and which fall to HPET hardware, this means that the call
has both the penalty of the syscall and of the uncached hw behind the
QPI or PCIe connection to the sought bridge. Nothing can me done
against the access latency, but the syscall overhead can be removed.
System already provides mappable /dev/hpetX devices, which gives
straight access to the HPET registers page.
Add yet another algorithm to the x86 'vdso' timehands. Libc is updated
to handle both RDTSC and HPET. For HPET, the index of the hpet device
to mmap is passed from kernel to userspace, index might be changed and
libc invalidates its mapping as needed.
Remove cpu_fill_vdso_timehands() KPI, instead require that
timecounters which can be used from userspace, to provide
tc_fill_vdso_timehands{,32}() methods. Merge i386 and amd64
libc/<arch>/sys/__vdso_gettc.c into one source file in the new
libc/x86/sys location. __vdso_gettc() internal interface is changed
to move timecounter algorithm detection into the MD code.
Measurements show that RDTSC even with the syscall overhead is faster
than userspace HPET access. But still, userspace HPET is three-four
times faster than syscall HPET on several Core2 and SandyBridge
machines.
Tested by: Howard Su <howard0su@gmail.com>
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
Differential revision: https://reviews.freebsd.org/D7473
Uses of commas instead of a semicolons can easily go undetected. The comma
can serve as a statement separator but this shouldn't be abused when
statements are meant to be standalone.
Detected with devel/coccinelle following a hint from DragonFlyBSD.
MFC after: 1 month
- Add constants for the fields in the root-entry table address register,
namely the root type type (RTT) and root table address (RTA) mask.
- Add macros for the bitmask of the domain ID field in the second word
of context table entries as well as a helper macro (DMAR_CTX2_GET_DID)
to extract the domain ID from a context table entry.
Reviewed by: kib
MFC after: 1 month
Sponsored by: Chelsio Communications
difference between files.
For pc98, put x86/mp_x86.c into the same place as used by i386 file list.
Fix typo in comment.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
This was only needed for Xen, and a better way to deal with this issue has
been found, so this commit can be reverted.
Sponsored by: Citrix Systems R&D
MFC after: 5 days
Reviewed by: kib
Differential revision: https://reviews.freebsd.org/D7363
Event channel handlers cannot be removed during resume because there might
be an interrupt thread running on a CPU currently blocked in the
cpususpend_handler, which prevents the call to intr_remove_handler from
finishing and completely freezes the system during resume. r291022 tried to
fix this by allowing recursion in intr_remove_handler, but that's clearly
not enough.
Instead don't remove the handlers at the interrupt resume phase, and let
each driver remove the handler by itself during resume. In order to do this,
change the opaque event channel handler cookie to use the global interrupt
vector instead of the event channel port. The event channel port cannot be
used because after resume all event channels are reset, and the port numbers
can change.
Sponsored by: Citrix Systems R&D
MFC after: 5 days
Since these pages are allocated from a narrow range of memory, this makes
the allocation more likely to succeed.
Suggested by: kib
Reviewed by: jkim, kib
MFC after: 2 months
Differential Revision: https://reviews.freebsd.org/D7154
Set vm_guest to a new enum value (VM_GUEST_KVM) when kvm is detected and use
vm_guest in conditionals testing for KVM.
Also, fix a conditional checking if we're running in a VM which caught only
the generic VM case, but not more specific VMs (KVM, VMWare, etc.). (Spotted
by: vangyzen).
Differential revision: https://reviews.freebsd.org/D7172
Sponsored by: Dell Inc.
Approved by: kib (mentor), vangyzen (mentor)
Reviewed by: alc
MFC after: 4 weeks
If the hypervisor version is smaller than 4.6.0. Xen commits 74fd00 and
70a3cb are required on the hypervisor side for this to be fixed, and those
are only included in 4.6.0, so stay on the safe side and disable MSI-X
interrupt migration on anything older than 4.6.0.
It should not cause major performance degradation unless a lot of MSI-X
interrupts are allocated.
Sponsored by: Citrix Systems R&D
MFC after: 3 days
Reviewed by: jhb
Differential revision: https://reviews.freebsd.org/D7148
The new 'machdep.disable_msix_migration' tunable can be set to 1 to
disable migration of MSI-X interrupts.
Xen versions prior to 4.6.0 do not properly handle updates to MSI-X
table entries after the initial write. In particular, the operation
to unmask a table entry after updating it during migration is not
propagated to the "real" table for passthrough devices causing the
interrupt to remain masked. At least some systems in EC2 are
affected by this bug when using SRIOV. The tunable can be set in
loader.conf as a workaround.
Submitted by: Jeremiah Lott <jlott@averesystems.com> (original patch)
Approved by: re (marius)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D6947
If the allocation attempt fails, we may otherwise VM_WAIT after a failed
attempt to reclaim contiguous memory in the requested range. After r297466,
this results in the thread going to sleep, causing a hang during boot.
Reviewed by: jkim, kib
Approved by: re (gjb)
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D6945
Reduce number of iterations used for calibrating ICR read loop. The
new number of iteration still gives the same ICR latency as before,
tested on Intel SandyBridge and Haswell machines, and on AMD. But it
significantly reduces the unneeded pause on boot in some VMs, from ~10
secs to less then 1 sec. It was reported to occur in bhyve on AMD
host.
Reported and tested by: avg
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
The existing version depends on register_t and uintptr_t, which are only
available when including headers such as <sys/types.h>. As this macro is
used by <sys/socket.h>, for example, it should be written in such a way
that it doesn't depend on those types.
In r227474, this header file was changed to define SIG_ATOMIC_{MIN,MAX}
in terms of LONG_{MIN,MAX}. Unlike all of the definitions in this header
file, LONG_{MIN,MAX} is provided by <limits.h>. Remove the dependency on
<limits.h> by using __LONG_{MIN,MAX} instead and including
<machine/_limits.h>.
This change is needed to make SIG_ATOMIC_{MIN,MAX} work without
including any other header files.
This header uses __INT_MIN and __INT_MAX, which is provided by
<machine/_limits.h>. This is needed to make <stdint.h>'s WCHAR_MIN and
WCHAR_MAX work without including other headers as well.
switching between LAPIC modes is not supported, and there is no need
to wait for IPI ack in x2APIC mode. So the calibrated delay is only
needed for !x2APIC.
This saves around a second of boot time on the real hardware for
x2APIC.
Sponsored by: The FreeBSD Foundation
Add implementations of bus_map/unmap_resource to the x86 nexus driver.
Change bus_activate/deactivate_resource to honor RF_UNMAPPED and to
use bus_map/unmap_resource to create/destroy the implicit mapping when
RF_UNMAPPED is not set.
Reviewed by: cem
Differential Revision: https://reviews.freebsd.org/D5237
Currently, Application Processors (non-boot CPUs) are started by
MD code at SI_SUB_CPU, but they are kept waiting in a "pen" until
SI_SUB_SMP at which point they are released to run kernel threads.
SI_SUB_SMP is one of the last SYSINIT levels, so APs don't enter
the scheduler and start running threads until fairly late in the
boot.
This change moves SI_SUB_SMP up to just before software interrupt
threads are created allowing the APs to start executing kernel
threads much sooner (before any devices are probed). This allows
several initialization routines that need to perform initialization
on all CPUs to now perform that initialization in one step rather
than having to defer the AP initialization to a second SYSINIT run
at SI_SUB_SMP. It also permits all CPUs to be available for
handling interrupts before any devices are probed.
This last feature fixes a problem on with interrupt vector exhaustion.
Specifically, in the old model all device interrupts were routed
onto the boot CPU during boot. Later after the APs were released at
SI_SUB_SMP, interrupts were redistributed across all CPUs.
However, several drivers for multiqueue hardware allocate N interrupts
per CPU in the system. In a system with many CPUs, just a few drivers
doing this could exhaust the available pool of interrupt vectors on
the boot CPU as each driver was allocating N * mp_ncpu vectors on the
boot CPU. Now, drivers will allocate interrupts on their desired CPUs
during boot meaning that only N interrupts are allocated from the boot
CPU instead of N * mp_ncpu.
Some other bits of code can also be simplified as smp_started is
now true much earlier and will now always be true for these bits of
code. This removes the need to treat the single-CPU boot environment
as a special case.
As a transition aid, the new behavior is available under a new kernel
option (EARLY_AP_STARTUP). This will allow the option to be turned off
if need be during initial testing. I plan to enable this on x86 by
default in a followup commit in the next few days and to have all
platforms moved over before 11.0. Once the transition is complete,
the option will be removed along with the !EARLY_AP_STARTUP code.
These changes have only been tested on x86. Other platform maintainers
are encouraged to port their architectures over as well. The main
things to check for are any uses of smp_started in MD code that can be
simplified and SI_SUB_SMP SYSINITs in MD code that can be removed in
the EARLY_AP_STARTUP case (e.g. the interrupt shuffling).
PR: kern/199321
Reviewed by: markj, gnn, kib
Sponsored by: Netflix
if specific CPU features are not present.
Some simulation environments, e.g. gem5, have been found to require more
TLB management from the kernel in certain setups. It is currently unclear why.
Turning on the workaround_erratum383 seems to help and make problems (panics)
go away.
Given this is a fairly uncommon environment so far, allowing the workaround
to be manually enabled from loader in order to make debugging and comparing
traces easier, but also to allow gem5 run FreeBSD in X86 timing mode, seems
to be the least intrusive option for now until the issue if fully understood.
Sponsored by: DARPA/AFRL
Reviewed by: kib, alc (earlier)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D6206
bus_get_cpus() returns a specified set of CPUs for a device. It accepts
an enum for the second parameter that indicates the type of cpuset to
request. Currently two valus are supported:
- LOCAL_CPUS (on x86 this returns all the CPUs in the package closest to
the device when DEVICE_NUMA is enabled)
- INTR_CPUS (like LOCAL_CPUS but only returns 1 SMT thread for each core)
For systems that do not support NUMA (or if it is not enabled in the kernel
config), LOCAL_CPUS fails with EINVAL. INTR_CPUS is mapped to 'all_cpus'
by default. The idea is that INTR_CPUS should always return a valid set.
Device drivers which want to use per-CPU interrupts should start using
INTR_CPUS instead of simply assigning interrupts to all available CPUs.
In the future we may wish to add tunables to control the policy of
INTR_CPUS (e.g. should it be local-only or global, should it ignore
SMT threads or not).
The x86 nexus driver exposes the internal set of interrupt CPUs from the
the x86 interrupt code via INTR_CPUS.
The ACPI bus driver and PCI bridge drivers use _PXM to return a suitable
LOCAL_CPUS set when _PXM exists and DEVICE_NUMA is enabled. They also and
the global INTR_CPUS set from the nexus driver with the per-domain set from
_PXM to generate a local INTR_CPUS set for child devices.
Compared to the r298933, this version uses 'struct _cpuset' in
<sys/bus.h> instead of 'cpuset_t' to avoid requiring <sys/param.h>
(<sys/_cpuset.h> still requires <sys/param.h> for MAXCPU even though
<sys/_bitset.h> does not after recent changes).
Instead of panicking when parsing an invalid ACPI SRAT table,
just ignore it, effectively disabling NUMA.
https://lists.freebsd.org/pipermail/freebsd-current/2016-May/060984.html
Reported and tested by: Bill O'Hanlon (bill.ohanlon at gmail.com)
Reviewed by: jhb
MFC after: 1 week
Relnotes: If dmesg shows "SRAT: Duplicate local APIC ID",
try updating your BIOS to fix NUMA support.
Sponsored by: Dell Inc.
bus_get_cpus() returns a specified set of CPUs for a device. It accepts
an enum for the second parameter that indicates the type of cpuset to
request. Currently two valus are supported:
- LOCAL_CPUS (on x86 this returns all the CPUs in the package closest to
the device when DEVICE_NUMA is enabled)
- INTR_CPUS (like LOCAL_CPUS but only returns 1 SMT thread for each core)
For systems that do not support NUMA (or if it is not enabled in the kernel
config), LOCAL_CPUS fails with EINVAL. INTR_CPUS is mapped to 'all_cpus'
by default. The idea is that INTR_CPUS should always return a valid set.
Device drivers which want to use per-CPU interrupts should start using
INTR_CPUS instead of simply assigning interrupts to all available CPUs.
In the future we may wish to add tunables to control the policy of
INTR_CPUS (e.g. should it be local-only or global, should it ignore
SMT threads or not).
The x86 nexus driver exposes the internal set of interrupt CPUs from the
the x86 interrupt code via INTR_CPUS.
The ACPI bus driver and PCI bridge drivers use _PXM to return a suitable
LOCAL_CPUS set when _PXM exists and DEVICE_NUMA is enabled. They also and
the global INTR_CPUS set from the nexus driver with the per-domain set from
_PXM to generate a local INTR_CPUS set for child devices.
Reviewed by: wblock (manpage)
Differential Revision: https://reviews.freebsd.org/D5519
This is going to be used by the Xen clock on Dom0 in order to set the RTC of
the host. The current logic in atrtc_settime is moved to atrtc_set and the
unused device_t parameter is removed from the atrtc_set function call so it
can be safely used by other callers.
Sponsored by: Citrix Systems R&D
Reviewed by: kib, jhb
Differential revision: https://reviews.freebsd.org/D6067
rounddown2 tends to produce longer lines than the original code
and when the code has a high indentation level it was not really
advantageous to do the replacement.
This tries to strike a balance between readability using the macros
and flexibility of having the expressions, so not everything is
converted.
If we reached MAXMEMDOM, we would previously try to insert an additional
element and only detect overflow after causing (probably trivial) memory
overflow. Instead, detect the ndomain > MAXMEMDOM case before we write past
the end.
Reported by: Coverity
CID: 1354783
Sponsored by: EMC / Isilon Storage Division
which queued invalidation completion interrupt is requested with
regard to the queued invalidation requests. In other words, setting
the value of the knob to N requests completion interrupt after N items
are processed. Existing behaviour is restored by setting
hw.dmar.batch_coalesce=1.
The knob significantly decreases the DMAR qi interrupt rate at the
cost of slightly longer DMAR map entries recycling.
Sponsored by: The FreeBSD Foundation
initially configured in the TSC deadline mode, eventtimer subsystem
can be switched to periodic, and then DCR register is loaded with
unitialized value.
Reset the LAPIC eventtimer frequency and min/max periods when changing
between deadline and counted periodic modes.
Reported and tested by: Vladimir Zakharov <zakharov.vv@gmail.com>
Sponsored by: The FreeBSD Foundation
Revert r292255 because it can create bounced regions without contiguous
page offsets, which is needed for USB devices.
Another solution would be to force bouncing the full buffer always (even
when only one page requires bouncing), but this seems overly complicated and
unnecessary, and it will probably involve using more bounce pages than the
current code.
Reported by: phk
system. This uses the hints mechnanism. This mostly works today
because when there's no static hints (the default), this value can be
fetched from the hint. When there is a static hints file, the hint
passed from the boot loader to the kernel is ignored, but for the BIOS
case we're able to find it anyway. However, with UEFI, the fallback
doesn't work, so we get a panic instead.
Switch to acpi.rsdp and use TUNABLE_ULONG_FETCH instead. Continue to
generate the old values to allow for transitions. In addition, fall
back to the old method if the new method isn't present.
Add comments about all this.
Differential Revision: https://reviews.freebsd.org/D5866
Some BIOSes disable AMD Topology extension on AMD Family 15h notebook
processors. We re-enable the extension, so that we can properly discover
core and cache topology. Linux seems to do the same.
Reported by: Johannes Dieterich <dieterich.joh@gmail.com>
Reviewed by: jhb, kib
Tested by: Johannes Dieterich <dieterich.joh@gmail.com>
(earlier version)
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D5883
VM_NUMA_ALLOC is used to enable use of domain-aware memory allocation in
the virtual memory system. DEVICE_NUMA is used to enable affinity
reporting for devices such as bus_get_domain().
MAXMEMDOM must still be set to a value greater than for any NUMA support
to be effective. Note that 'cpuset -gd' always works if MAXMEMDOM is
enabled and the system supports NUMA.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D5782
It is needed by the hypervisor FreeBSD guest to allocate/free private
interrupt vectors.
Reviewed by: kib, jhb, Dexuan Cui <decui microsoft com>
Sponsored by: Microsoft OSTC
Differential Revision: https://reviews.freebsd.org/D5849
Previously, the code determined a topology of processing units
(hardware threads, cores, packages) and then deduced a cache topology
using certain assumptions. The new code builds a topology that
includes both processing units and caches using the information
provided by the hardware.
At the moment, the discovered full topology is used only to creeate
a scheduling topology for SCHED_ULE.
There is no KPI for other kernel uses.
Summary:
- based on APIC ID derivation rules for Intel and AMD CPUs
- can handle non-uniform topologies
- requires homogeneous APIC ID assignment (same bit widths for ID
components)
- topology for dual-node AMD CPUs may not be optimal
- topology for latest AMD CPU models may not be optimal as the code is
several years old
- supports only thread/package/core/cache nodes
Todo:
- AMD dual-node processors
- latest AMD processors
- NUMA nodes
- checking for homogeneity of the APIC ID assignment across packages
- more flexible cache placement within topology
- expose topology to userland, e.g., via sysctl nodes
Long term todo:
- KPI for CPU sharing and affinity with respect to various resources
(e.g., two logical processors may share the same FPU, etc)
Reviewed by: mav
Tested by: mav
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D2728
Simplify and unify placeholder type definitions.
Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D5771
