MFC @248461

Make kern_nanosleep() and pause_sbt() to use per-CPU sleep queues.
This removes significant sleep queue lock congestion on multithreaded
microbenchmarks, making them scale to multiple CPUs almost lin

Make kern_nanosleep() and pause_sbt() to use per-CPU sleep queues.
This removes significant sleep queue lock congestion on multithreaded
microbenchmarks, making them scale to multiple CPUs almost linearly.

show more ...

MFC @248093

MFcalloutng:
Introduce sbt variants of msleep(), msleep_spin(), pause(), tsleep() in
the KPI, allowing to specify timeout in 'sbintime_t' rather than ticks.

Sponsored by: Google Summer of Code 2012,

MFcalloutng:
Introduce sbt variants of msleep(), msleep_spin(), pause(), tsleep() in
the KPI, allowing to specify timeout in 'sbintime_t' rather than ticks.

Sponsored by: Google Summer of Code 2012, iXsystems inc.
Tested by: flo, marius, ian, markj, Fabian Keil

show more ...

MFcalloutng (r244355):
Make loadavg calculation callout direct. There are several reasons for it:
- it is very simple and doesn't worth context switch to SWI;
- since SWI is no longer used here, we

MFcalloutng (r244355):
Make loadavg calculation callout direct. There are several reasons for it:
- it is very simple and doesn't worth context switch to SWI;
- since SWI is no longer used here, we can remove twelve years old hack,
excluding this SWI from from the loadavg statistics;
- it fixes problem when eventtimer (HPET) shares interrupt with some other
device, and that interrupt thread counted as permanent loadavg of 1; now
loadavg accounted before that interrupt thread is scheduled.

Sponsored by: Google Summer of Code 2012, iXsystems inc.
Tested by: flo, marius, ian, Fabian Keil, markj

show more ...

IFC @247348.

Sync with HEAD.

IFC @ r245178

Fix some minor inaccuracies introduced in r243251.
Also correct the comment in kern_synch.c which was the source of the
problematic text.

Reviewed by: kib (previous version)
Approved by: hrs (mentor)

IFC @ r238370

IFC @ r236291.
Diff reductions to the enclosure driver made in r235911.

Merge head r233826 through r236168.

Implement the DTrace sched provider. This implementation aims to be
compatible with the sched provider implemented by Solaris and its open-
source derivatives. Full documentation of the sched provi

Implement the DTrace sched provider. This implementation aims to be
compatible with the sched provider implemented by Solaris and its open-
source derivatives. Full documentation of the sched provider can be found
on Oracle's DTrace wiki pages.

Note that for compatibility with scripts originally written for Solaris,
serveral probes are defined that will never fire. These probes are defined
to fire when Solaris-specific features perform certain actions. As these
features are not present in FreeBSD, the probes can never fire.

Also, I have added a two probes that are not defined in Solaris, lend-pri
and load-change. These probes have been added to make it possible to
collect schedgraph data with DTrace.

Finally, a few probes are defined in Solaris to take a cpuinfo_t *
argument. As it was not immediately clear to me how to translate that to
FreeBSD, currently those probes are passed NULL in place of a cpuinfo_t *.

Sponsored by: Sandvine Incorporated
MFC after: 2 weeks

show more ...

MFC

Merge head r233826 through r234834.

IFC @ r234692

sys/amd64/include/cpufunc.h
sys/amd64/include/fpu.h
sys/amd64/amd64/fpu.c
sys/amd64/vmm/vmm.c

- Add API to allow vmm FPU state init/save/restore.

FP stuff discussed with: kib

Include the associated wait channel message for context switch ktrace
records. kdump supports both the old and new messages.

Submitted by: Andrey Zonov andrey zonov org
MFC after: 1 week

IFC @230489 (pending review).

IFC to head to catch up the bhyve branch

Approved by: grehan@

panic: add a switch and infrastructure for stopping other CPUs in SMP case

Historical behavior of letting other CPUs merily go on is a default for
time being. The new behavior can be switched on vi

panic: add a switch and infrastructure for stopping other CPUs in SMP case

Historical behavior of letting other CPUs merily go on is a default for
time being. The new behavior can be switched on via
kern.stop_scheduler_on_panic tunable and sysctl.

Stopping of the CPUs has (at least) the following benefits:
- more of the system state at panic time is preserved intact
- threads and interrupts do not interfere with dumping of the system
state

Only one thread runs uninterrupted after panic if stop_scheduler_on_panic
is set. That thread might call code that is also used in normal context
and that code might use locks to prevent concurrent execution of certain
parts. Those locks might be held by the stopped threads and would never
be released. To work around this issue, it was decided that instead of
explicit checks for panic context, we would rather put those checks
inside the locking primitives.

This change has substantial portions written and re-written by attilio
and kib at various times. Other changes are heavily based on the ideas
and patches submitted by jhb and mdf. bde has provided many insights
into the details and history of the current code.

The new behavior may cause problems for systems that use a USB keyboard
for interfacing with system console. This is because of some unusual
locking patterns in the ukbd code which have to be used because on one
hand ukbd is below syscons, but on the other hand it has to interface
with other usb code that uses regular mutexes/Giant for its concurrency
protection. Dumping to USB-connected disks may also be affected.

PR: amd64/139614 (at least)
In cooperation with: attilio, jhb, kib, mdf
Discussed with: arch@, bde
Tested by: Eugene Grosbein <eugen@grosbein.net>,
gnn,
Steven Hartland <killing@multiplay.co.uk>,
glebius,
Andrew Boyer <aboyer@averesystems.com>
(various versions of the patch)
MFC after: 3 months (or never)

show more ...

Make sure the description of pause() is
equivalent to its implementation.
No code change.

Suggested by: Bruce Evans
MFC after: 3 days

IFC @ r227804

Pull in the virtio drivers from head.

Given that the typical usage of pause() is pause("zzz", hz / N), where N can
be greater than hz in some cases, simply ignore a timeout value of zero.

Suggested by: Bruce Evans
MFC after: 1 week

Minor style change:
Simplify the description of pause() and shorten the KASSERT message in pause.
Also add a clamp for the timo argument in the non-KASSERT case.

Suggested by: Bruce Evans
MFC after:

Minor style change:
Simplify the description of pause() and shorten the KASSERT message in pause.
Also add a clamp for the timo argument in the non-KASSERT case.

Suggested by: Bruce Evans
MFC after: 1 week

show more ...

Simplify the usb_pause_mtx() function by factoring out the generic parts
to the kernel's pause() function. The pause() function can now be used
when cold != 0. Also assert that the timeout in system

Simplify the usb_pause_mtx() function by factoring out the generic parts
to the kernel's pause() function. The pause() function can now be used
when cold != 0. Also assert that the timeout in system ticks must be
positive.

Suggested by: Bruce Evans
MFC after: 1 week

show more ...