to VPO_UNMANAGED (and also making the flag protected by the vm object
lock, instead of vm page queue lock).
- Mark the fake pages with both PG_FICTITIOUS (as it is now) and
VPO_UNMANAGED. As a consequence, pmap code now can use use just
VPO_UNMANAGED to decide whether the page is unmanaged.
Reviewed by: alc
Tested by: pho (x86, previous version), marius (sparc64),
marcel (arm, ia64, powerpc), ray (mips)
Sponsored by: The FreeBSD Foundation
Approved by: re (bz)
NFSCL, NFSD instead of NFSCLIENT, NFSSERVER since
NFSCL and NFSD are now the defaults. The client change is
needed for diskless configurations, so that the root
mount works for fstype nfs.
Reported by seanbru at yahoo-inc.com for i386/XEN.
Approved by: re (hrs)
When the last, possibly partially filled buffer is flushed, we didn't
reset fragsz to 0 and as such would stop reflecting reality.
- Use __FBSDID.
- Wrap a too long line.
Approved by: re (kib)
MFC after: 1 week
This patch is going to help in cases like mips flavours where you
want a more granular support on MAXCPU.
No MFC is previewed for this patch.
Tested by: pluknet
Approved by: re (kib)
sintrcnt/sintrnames which are symbols containing the size of the 2
tables.
- For amd64/i386 remove the storage of intr* stuff from assembly files.
This area can be widely improved by applying the same to other
architectures and likely finding an unified approach among them and
move the whole code to be MI. More work in this area is expected to
happen fairly soon.
No MFC is previewed for this patch.
Tested by: pluknet
Reviewed by: jhb
Approved by: re (kib)
cycle mode as timecounter just works fine. My best guess is that a firmware
update has fixed this, check at run-time whether it advances and use a
positive quality if it does. The latter will cause this timecounter to be
used instead of the tick counter based one, which just sucks for SMP.
- Remove a redundant NULL assignment from the timecounter initialization.
as STX_CTRL_PERF_CNT_CNT0_SHIFT actually is zero, if we were using the
second counter in the upper 32 bits this would be required though as the MI
timecounter code doesn't support 64-bit counters/counter registers.
- Remove a redundant NULL assignment from the timecounter initialization.
This is just a simple approach. For reasons unknown OpenSolaris uses a
more sophisticated one involving IPIing the remaining CPUs in reverse
order after the first batch of 32.
erratum causing them to trigger stray vector interrupts accompanied by a
state in which they even fault on locked TLB entries. Just retrying the
instruction in that case gets the CPU back on track though. OpenSolaris
also just ignores a certain number of stray vector interrupts.
While at it, implement the stray vector interrupt handling for SPARC64-VI
which use these for indicating uncorrectable errors in interrupt packets.
the TLBs in order to get rid of the user mappings but instead traverse
them an flush only the latter like we also do for the Spitfire-class.
Also flushing the unlocked kernel entries can cause instant faults which
when called from within cpu_switch() are handled with the scheduler lock
held which in turn can cause timeouts on the acquisition of the lock by
other CPUs. This was easily seen with a 16-core V890 but occasionally
also happened with 2-way machines.
While at it, move the SPARC64-V support code entirely to zeus.c. This
causes a little bit of duplication but is less confusing than partially
using Cheetah-class bits for these.
- For SPARC64-V ensure that 4-Mbyte page entries are stored in the 1024-
entry, 2-way set associative TLB.
- In {d,i}tlb_get_data_sun4u() turn off the interrupts in order to ensure
that ASI_{D,I}TLB_DATA_ACCESS_REG actually are read twice back-to-back.
Tested by: Peter Jeremy (16-core US-IV), Michael Moll (2-way SPARC64-V)
more explicit comments about what's going on and what future maintainers
need to do when e.g. adding a new operation to a sys_machdep.c.
Approved by: mentor(rwatson), re(bz)
interrupts. Bringup on additional machine models repeatedly reveals
firmware that enables interrupts behind our back, causing the console
to be flooded otherwise.
- As with the regular interrupt counters using uint16_t instead of
u_long for counting the stray vector interrupts should be more than
sufficient.
- Cache the interrupt vector in intr_stray_vector().
have to ignore it when sending the IPI anyway. Actually I can't think of
a good reason why this ever was done that way in the first place as it's
not even usefull for debugging.
While at it replace the use of pc_other_cpus as it's slated for deorbit.
RSF_FATAL we need to switch to alternate globals for KSTACK_CHECK just
like tl1_data_excptn(_trap) does. This is more or less cosmetic because
in case RSF_FATAL is called we're already heading south.
- Correct an END().
- Read the window state from the correct register for a CATR().
more than three temporary register in several places CATR() is used so
this code trades instructions in for registers. Actually, this still isn't
sufficient and CATR() has the side-effect of clobbering %y. Luckily, with
the current uses of CATR() this either doesn't matter or we are able to
(save and) restore it.
Now that there's only one use of AND() and TEST() left inline these.
This introduce all the underlying support for making this possible (via
the function cpusetobj_strscan() and keeps ktr_cpumask exported. sparc64
implements its own assembly primitives for tracing events and needs to
properly check it. Anyway the sparc64 logic is not implemented yet due
to lack of knowledge (by me) and time (by marius), but it is just a
matter of using ktr_cpumask when possible.
Tested and fixed by: pluknet
Reviewed by: marius
be brought up in the order they are enumerated in the device tree (in
particular, that thread 0 on each core be brought up first). The SLIST
through which we loop to start the CPUs has all of its entries added with
SLIST_INSERT_HEAD(), which means it is in reverse order of enumeration
and so AP startup would always fail in such situations (causing a machine
check or RTAS failure). Fix this by changing the SLIST into an STAILQ,
and inserting new CPUs at the end.
Reviewed by: jhb
Some files keep the SUN4V tags as a code reference, for the future,
if any rewamped sun4v support wants to be added again.
Reviewed by: marius
Tested by: sbruno
Approved by: re
architectures (i386, for example) the virtual memory space may be
constrained enough that 2MB is a large chunk. Use 64K for arches
other than amd64 and ia64, with special handling for sparc64 due to
differing hardware.
Also commit the comment changes to kmem_init_zero_region() that I
missed due to not saving the file. (Darn the unfamiliar development
environment).
Arch maintainers, please feel free to adjust ZERO_REGION_SIZE as you
see fit.
Requested by: alc
MFC after: 1 week
MFC with: r221853
pc_cpumask were changed to cpuset_t. This now calculates the cpumask based
on pc_cpuid itself as pc_cpumask is slated for being deorbited. Note that
this needs r221750 to be MFC'ed in order to compile.
This seems to work fine but after a few dozens of successful IPIs something
suddenly adds pc_cpuid to pc_other_cpus, causing the respective assertions
in mp_machdep.c to be triggered when the latter is used as the base for the
targets.
must not, otherwise we tell the CPU to IPI itself, which the sun4u CPUs don't
support. For reasons unknown so far MD and MI IPI use actually still triggers
that assertion though.
This now calculates pc_cpumask based on pc_cpuid itself as the former is
slated for being deorbited.
This branch now at least boots UP again. MP needs more things converted and
the existing conversion from cpumask_t to cpuset_t still has bugs.
versions instead. They were never needed as bus_generic_intr() and
bus_teardown_intr() had been changed to pass the original child device up
in 42734, but the ISA bus was not converted to new-bus until 45720.
driver would verify that requests for child devices were confined to any
existing I/O windows, but the driver relied on the firmware to initialize
the windows and would never grow the windows for new requests. Now the
driver actively manages the I/O windows.
This is implemented by allocating a bus resource for each I/O window from
the parent PCI bus and suballocating that resource to child devices. The
suballocations are managed by creating an rman for each I/O window. The
suballocated resources are mapped by passing the bus_activate_resource()
call up to the parent PCI bus. Windows are grown when needed by using
bus_adjust_resource() to adjust the resource allocated from the parent PCI
bus. If the adjust request succeeds, the window is adjusted and the
suballocation request for the child device is retried.
When growing a window, the rman_first_free_region() and
rman_last_free_region() routines are used to determine if the front or
end of the existing I/O window is free. From using that, the smallest
ranges that need to be added to either the front or back of the window
are computed. The driver will first try to grow the window in whichever
direction requires the smallest growth first followed by the other
direction if that fails.
Subtractive bridges will first attempt to satisfy requests for child
resources from I/O windows (including attempts to grow the windows). If
that fails, the request is passed up to the parent PCI bus directly
however.
The PCI-PCI bridge driver will try to use firmware-assigned ranges for
child BARs first and only allocate a "fresh" range if that specific range
cannot be accommodated in the I/O window. This allows systems where the
firmware assigns resources during boot but later wipes the I/O windows
(some ACPI BIOSen are known to do this) to "rediscover" the original I/O
window ranges.
The ACPI Host-PCI bridge driver has been adjusted to correctly honor
hw.acpi.host_mem_start and the I/O port equivalent when a PCI-PCI bridge
makes a wildcard request for an I/O window range.
The new PCI-PCI bridge driver is only enabled if the NEW_PCIB kernel option
is enabled. This is a transition aide to allow platforms that do not
yet support bus_activate_resource() and bus_adjust_resource() in their
Host-PCI bridge drivers (and possibly other drivers as needed) to use the
old driver for now. Once all platforms support the new driver, the
kernel option and old driver will be removed.
PR: kern/143874 kern/149306
Tested by: mav
NFS client (which I guess is no longer experimental). The fstype "newnfs"
is now "nfs" and the regular/old NFS client is now fstype "oldnfs".
Although mounts via fstype "nfs" will usually work without userland
changes, an updated mount_nfs(8) binary is needed for kernels built with
"options NFSCL" but not "options NFSCLIENT". Updated mount_nfs(8) and
mount(8) binaries are needed to do mounts for fstype "oldnfs".
The GENERIC kernel configs have been changed to use options
NFSCL and NFSD (the new client and server) instead of NFSCLIENT and NFSSERVER.
For kernels being used on diskless NFS root systems, "options NFSCL"
must be in the kernel config.
Discussed on freebsd-fs@.
stack. It means that all legacy ATA drivers are disabled and replaced by
respective CAM drivers. If you are using ATA device names in /etc/fstab or
other places, make sure to update them respectively (adX -> adaY,
acdX -> cdY, afdX -> daY, astX -> saY, where 'Y's are the sequential
numbers for each type in order of detection, unless configured otherwise
with tunables, see cam(4)).
ataraid(4) functionality is now supported by the RAID GEOM class.
To use it you can load geom_raid kernel module and use graid(8) tool
for management. Instead of /dev/arX device names, use /dev/raid/rX.
r220375 all drivers enabled in the sparc64 GENERIC should be either
correctly using bus_dmamap_sync(9) calls or supply BUS_DMA_COHERENT
when appropriate or as a workaround for missing bus_dmamap_sync(9)
calls (sound(4) drivers and partially sym(4)). In at least some
configurations taking advantage of the streaming cache results in
a modest performance improvement.
- Remove the memory barrier for BUS_DMASYNC_PREREAD which as the
comment already suggested is bogus.
- Add my copyright for having implemented several things like support
for the Fire and Oberon IOMMUs, taking over PROM IOMMU mappings etc.
Introduce the AHB glue for Atheros embedded systems. Right now it's
hard-coded for the AR9130 chip whose support isn't yet in this HAL;
it'll be added in a subsequent commit.
Kernel configuration files now need both 'ath' and 'ath_pci' devices; both
modules need to be loaded for the ath device to work.
the iommu(4) provided one, i.e. in case of Hummingbird and Sabre bridges,
otherwise just use the iommu(4) one. This also fixes a bug introduced in
r220039 which caused an empty DMA method table to be used for the second
of a pair of Psycho bridges.
syncing for Hummingbird and Sabre bridges should be applied with every
BUS_DMASYNC_POSTREAD instead of in a wrapper around interrupt handlers
for devices behind PCI-PCI bridges only as suggested by the documentation
(code for the latter actually exists in OpenSolaris but is disabled by
default), which also makes more sense.
- Take advantage of the ofw_pci_setup_device method introduced in r220038
for disabling bus parking for certain EBus bridges in order to
- Mark some unused parameters as such.
register changes when compiled with SCHIZO_DEBUG and take advantage
of them.
- Add support for the XMITS Fireplane/Safari to PCI-X bridges. I tought
I'd need this for a Sun Fire 3800, which then turned out to not being
equipped with such a bridge though. The support for these should be
complete but given that it hasn't actually been tested probing is
disabled for now.
This required a way to alter the XMITS configuration in case a PCI-X
device is found further down the device tree so the sparc64 specific
ofw_pci kobj was revived with a ofw_pci_setup_device method, which is
called by the ofw_pcibus code for every device added.
- A closer inspection of the OpenSolaris code indicates that consistent
DMA flushing/syncing as well as the block store workaround should be
applied with every BUS_DMASYNC_POSTREAD instead of in a wrapper around
interrupt handlers for devices behind PCI-PCI bridges only as suggested
by the documentation (code for the latter actually exists in OpenSolaris
but is disabled by default), which also makes more sense.
- Add a workaround for Casinni/Skyhawk combinations. Chances are that
this solves the crashes seen when using the the on-board Casinni NICs
of Sun Fire V480 equipped with centerplanes other than 501-6780 or
501-6790. This also takes advantage of the ofw_pci_setup_device method.
- Mark some unused parameters as such.
- A closer inspection of the OpenSolaris code indicates the block store
workaround is only necessary in case of BUS_DMASYNC_POSTREAD.
- Mark some unused parameters as such.
- Emitt an error when encountering an unsupported and in case of the
kernel also for unaligned relocations.
- Fix R_SPARC_LOX10 relocations. Apparently these are hardly ever used.
- Add the _RF_X committed in r212998 also to the tables in the sparc64
reloc.c in order reduce differences between the kernel and the userland
source. This results in no functional change though.
- Fix further inconsistencies in the abbreviations of the names of the
relocations.
- Further whitespace fixes.
Obtained from: NetBSD [1]
explicit process at fork trampoline path instead of eventhadler(schedtail)
invocation for each child process.
Remove eventhandler(schedtail) code and change linux ABI to use newly added
sysvec method.
While here replace explicit comparing of module sysentvec structure with the
newly created process sysentvec to detect the linux ABI.
Discussed with: kib
MFC after: 2 Week
values for resolved symbols relative to relocbase instead of sections
so detect this case and handle as appropriate, which allows using
kernel modules linked with affected versions of binutils. Actually I
think this is a bug in binutils but given that apparently nobody
complained for nearly six years and powerpc has basically the same
workaround I decided to put it in for the sparc64 kernel, too.
- Fix R_SPARC_HIX22 relocations. Apparently these are hardly ever used.
should_yield(). Use this in various places. Encapsulate the common
case of check-and-yield into a new function maybe_yield().
Change several checks for a magic number of iterations to use
should_yield() instead.
MFC after: 1 week
sf buf allocation, use wakeup() instead of wakeup_one() to notify sf
buffer waiters about free buffer.
sf_buf_alloc() calls msleep(PCATCH) when SFB_CATCH flag was given,
and for simultaneous wakeup and signal delivery, msleep() returns
EINTR/ERESTART despite the thread was selected for wakeup_one(). As
result, we loose a wakeup, and some other waiter will not be woken up.
Reported and tested by: az
Reviewed by: alc, jhb
MFC after: 1 week
Compile sys/dev/mem/memutil.c for all supported platforms and remove now
unnecessary dev_mem_md_init(). Consistently define mem_range_softc from
mem.c for all platforms. Add missing #include guards for machine/memdev.h
and sys/memrange.h. Clean up some nearby style(9) nits.
MFC after: 1 month
TSB is located within the 32-bit address space, which held true as long as
we were using virtual addresses magic-mapped before the location of the
kernel for addressing it. However, with r216803 in place when possible we
address it via its physical address instead, which on machines like Sun Fire
V880 have no physical memory in the 32-bit address space at all requires
to use 64-bit addressing. When using physical addressing it still should
be safe to assume that we can just ignore the lowest 10 bits of the address
as a minor optimization as we did before r216803.
architecture macros (__mips_n64, __powerpc64__) when 64 bit types (and
corresponding macros) are different from 32 bit. [1]
Correct the type of INT64_MIN, INT64_MAX and UINT64_MAX.
Define (U)INTMAX_C as an alias for (U)INT64_C matching the type definition
for (u)intmax_t. Do this on all architectures for consistency.
Suggested by: bde [1]
Approved by: kib (mentor)
On some architectures UCHAR_MAX and USHRT_MAX had type unsigned int.
However, lacking integer suffixes for types smaller than int, their type
should correspond to that of an object of type unsigned char (or short)
when used in an expression with objects of type int. In that case unsigned
char (short) are promoted to int (i.e. signed) so the type of UCHAR_MAX and
USHRT_MAX should also be int.
Where MIN/MAX constants implicitly have the correct type the suffix has
been removed.
While here, correct some comments.
Reviewed by: bde
Approved by: kib (mentor)
and switch sparc64 to use the first one for bus error filter handlers of
bridge drivers instead of (ab)using INTR_FAST for that so we eventually
can get rid of the latter.
Reviewed by: jhb
MFC after: 1 month
functions, otherwise if we get preempted after checking whether a certain
pmap is active on the current CPU but before disabling interrupts we might
operate on an outdated state as the pmap might have been deactivated in
the meantime. As the same issue may arises when the TLB demap function is
interrupted by a TLB demap IPI, just entering a critical section before
the check isn't sufficient so we have to fully disable interrupts instead.
MFC after: 3 days
which takes an physical address instead of an virtual one, for loading TTEs
of the kernel TSB so we no longer need to lock the kernel TSB into the dTLB,
which only has a very limited number of lockable dTLB slots. The net result
is that we now basically can handle a kernel TSB of any size and no longer
need to limit the kernel address space based on the number of dTLB slots
available for locked entries. Consequently, other parts of the trap handlers
now also only access the the kernel TSB via its physical address in order
to avoid nested traps, as does the PMAP bootstrap code as we haven't taken
over the trap table at that point, yet. Apart from that the kernel TSB now
is accessed via a direct mapping when we are otherwise taking advantage of
ASI_ATOMIC_QUAD_LDD_PHYS so no further code changes are needed. Most of this
is implemented by extending the patching of the TSB addresses and mask as
well as the ASIs used to load it into the trap table so the runtime overhead
of this change is rather low. Currently the use of ASI_ATOMIC_QUAD_LDD_PHYS
is not yet enabled on SPARC64 CPUs due to lack of testing and due to the
fact it might require minor adjustments there.
Theoretically it should be possible to use the same approach also for the
user TSB, which already is not locked into the dTLB, avoiding nested traps.
However, for reasons I don't understand yet OpenSolaris only does that with
SPARC64 CPUs. On the other hand I think that also addressing the user TSB
physically and thus avoiding nested traps would get us closer to sharing
this code with sun4v, which only supports trap level 0 and 1, so eventually
we could have a single kernel which runs on both sun4u and sun4v (as does
Linux and OpenBSD).
Developed at and committed from: 27C3
STICK/STICK_COMPARE independently of the selected instruction set by
TICK_COMPARE so tick.c as of r214358 once again can be compiled with
gcc -mcpu=v9 for reference purposes.
kernel address space in order to leave space for the buffer cache, pipes,
thread stacks, etc on machines with more physical memory until we take
advantage of ASI_ATOMIC_QUAD_LDD_PHYS on CPUs providing it so we don't need
to lock the kernel TSB pages into the dTLB, basically making the entire
64-bit kernel address space available on relevant machines.
Submitted by: alc
Passing a count of zero on i386 and amd64 for [I386|AMD64]_BUS_SPACE_MEM
causes a crash/hang since the 'loop' instruction decrements the counter
before checking if it's zero.
PR: kern/80980
Discussed with: jhb
DEBUG_MEMGUARD panics early in kmeminit() with the message
"kmem_suballoc: bad status return of 1" because of zero "size" argument
passed to kmem_suballoc() due to "vm_kmem_size_max" being zero.
The problem also exists on ia64.
creation of large page mappings in the pmap, it can provide modest
performance benefits. In particular, for a "buildworld" on a 2x 1GHz
Ultrasparc IIIi it reduced the wall clock time by 2.2% and the system
time by 12.6%.
Tested by: marius@
contents of the ones that were not empty were stale and unused.
- Now that <machine/mutex.h> no longer exists, there is no need to allow it
to override various helper macros in <sys/mutex.h>.
- Rename various helper macros for low-level operations on mutexes to live
in the _mtx_* or __mtx_* namespaces. While here, change the names to more
closely match the real API functions they are backing.
- Drop support for including <sys/mutex.h> in assembly source files.
Suggested by: bde (1, 2)
work properly with single-stepping in a kernel debugger. Specifically,
these routines have always disabled interrupts before increasing the nesting
count and restored the prior state of interrupts after decreasing the nesting
count to avoid problems with a nested interrupt not disabling interrupts
when acquiring a spin lock. However, trap interrupts for single-stepping
can still occur even when interrupts are disabled. Now the saved state of
interrupts is not saved in the thread until after interrupts have been
disabled and the nesting count has been increased. Similarly, the saved
state from the thread cannot be read once the nesting count has been
decreased to zero. To fix this, use temporary variables to store interrupt
state and shuffle it between the thread's MD area and the appropriate
registers.
In cooperation with: bde
MFC after: 1 month
need locking as otherwise we may race against the other parts of the
MD code which expects a consistent state of these. While at it move
the resetting of the pmap before entering it in the TSB.
- Spell a 0 as TLB_CTX_KERNEL.
introduce function pointers once set up to the respective implementation
for reading the (S)TICK and writing the (S)STICK_COMPARE registers as a
compromise between duplicating code and selecting between different
implementations during execution over and over again, similar to what is
done elsewhere in the MD in order to support different CPU models that
won't ever change at runtime.
- In the remaining tick interrupt handler further push down disabling of
interrupts to the periodic case as it isn't necessary here in one-shot
mode at all.
a critical section as apparently required by both. I don't think either
belongs in the event timer front-ends but the callback should handle
this as necessary instead just like for example intr_event_handle()
does but this is how the other architectures currently handle it, either
explicitly or implicitly.
- Further rename and reword references to hardclock as this front-end no
longer has a notion of actually calling it.
drift in order to achieve a more stable clock as the tick intervals may
vary in the first place. In fact I haven't seen this code kick in when
in oneshot-mode so just skip it in that case.
- There's no need to explicitly stop the (S)TICK counter in oneshot-mode
with every tick as it just won't trigger again with the (S)TICK compare
register set to a value in the past (with a wrap-around once every ~195
years of uptime at 1.5 GHz this isn't something we have to worry about
in practice).
- Given that we'll disable interrupts completely anyway there's no
need to enter critical sections.
what is done on other platforms. Unlike as with the sched_throw(NULL)
called on BSPs during their startup apparently there's nothing which will
reliably lower it on APs. I'm unsure why this only came up on V215 though,
breaking these with r207248. My best guess is that these are the only
supported ones so far fast enough to loose some race.
PR: 151404
MFC after: 3 days
to the expected type so they work like the corresponding __bswapN_var()
functions and the compiler doesn't complain when arguments of different
width are passed.
The check for alignment should be made against the physical address and not
the virtual address that maps it.
Sponsored by: NetApp
Submitted by: Will McGovern (will at netapp dot com)
Reviewed by: mjacob, jhb
the location, apply elf_relocaddr to the symbol value to have right
values for the symbols from dpcpu segment.
PR: kern/147769
Discussed with: avg
Tested by: marius
MFC after: 2 weeks
additionally takes advantage of the prefetch cache of these CPUs.
Unlike the uncommitted US-III version, which provide no measurable
speedup or even resulted in a slight slowdown on certain CPUs models
compared to using the US-I version with these, the SPARC64 version
actually results in a slight improvement.
- make dflt_lock() always panic,
- add kludge to use contigmalloc() when the alignment is larger than the size
and print a diagnostic when we didn't satisfy the alignment.
unlikely that support for these ever will be implemented on sparc64 as
the IOMMUs are able to translate to up to the maximum physical address
supported by the respective machine, bypassing the IOMMU is affected
by hardware errata and being able to support DMA engines which cannot
do at least 32-bit DMA does not justify the costs.
- The page zeroing in uma_small_alloc() may use the VIS-based block zero
function so take advantage of it.
of small maxsize and "large" (including BUS_SPACE_UNRESTRICTED) nsegments
parameters. Generally using a presz of 0 (which indeed might indicate the
use of bogus parameters for DMA tag creation) is not fatal, it just means
that no additional DVMA space will be preallocated.
The main goal of this is to generate timer interrupts only when there is
some work to do. When CPU is busy interrupts are generating at full rate
of hz + stathz to fullfill scheduler and timekeeping requirements. But
when CPU is idle, only minimum set of interrupts (down to 8 interrupts per
second per CPU now), needed to handle scheduled callouts is executed.
This allows significantly increase idle CPU sleep time, increasing effect
of static power-saving technologies. Also it should reduce host CPU load
on virtualized systems, when guest system is idle.
There is set of tunables, also available as writable sysctls, allowing to
control wanted event timer subsystem behavior:
kern.eventtimer.timer - allows to choose event timer hardware to use.
On x86 there is up to 4 different kinds of timers. Depending on whether
chosen timer is per-CPU, behavior of other options slightly differs.
kern.eventtimer.periodic - allows to choose periodic and one-shot
operation mode. In periodic mode, current timer hardware taken as the only
source of time for time events. This mode is quite alike to previous kernel
behavior. One-shot mode instead uses currently selected time counter
hardware to schedule all needed events one by one and program timer to
generate interrupt exactly in specified time. Default value depends of
chosen timer capabilities, but one-shot mode is preferred, until other is
forced by user or hardware.
kern.eventtimer.singlemul - in periodic mode specifies how much times
higher timer frequency should be, to not strictly alias hardclock() and
statclock() events. Default values are 2 and 4, but could be reduced to 1
if extra interrupts are unwanted.
kern.eventtimer.idletick - makes each CPU to receive every timer interrupt
independently of whether they busy or not. By default this options is
disabled. If chosen timer is per-CPU and runs in periodic mode, this option
has no effect - all interrupts are generating.
As soon as this patch modifies cpu_idle() on some platforms, I have also
refactored one on x86. Now it makes use of MONITOR/MWAIT instrunctions
(if supported) under high sleep/wakeup rate, as fast alternative to other
methods. It allows SMP scheduler to wake up sleeping CPUs much faster
without using IPI, significantly increasing performance on some highly
task-switching loads.
Tested by: many (on i386, amd64, sparc64 and powerc)
H/W donated by: Gheorghe Ardelean
Sponsored by: iXsystems, Inc.
This reflects actual type used to store and compare child device orders.
Change is mostly done via a Coccinelle (soon to be devel/coccinelle)
semantic patch.
Verified by LINT+modules kernel builds.
Followup to: r212213
MFC after: 10 days
In particular, provide pagesize and pagesizes array, the canary value
for SSP use, number of host CPUs and osreldate.
Tested by: marius (sparc64)
MFC after: 1 month
td_critnest > 1 when not already running on the desired CPU read the
TICK counter of the BSP via a direct cross trap request in that case
instead.
- Treat the STICK based timecounter the same way as the TICK based one
regarding its quality and obtaining the counter value from the BSP.
Like the TICK timers the STICK ones also are only synchronized during
their startup (which might not result in good synchronicity in the
first place) but not afterwards and might drift over time, causing
problems when the time is read from different CPUs (see r135972).
