Commit Graph

286 Commits

Author SHA1 Message Date
Adrian Bunk
cdb0452789 [PATCH] kill include/linux/platform.h, default_idle() cleanup
include/linux/platform.h contained nothing that was actually used except
the default_idle() prototype, and is therefore removed by this patch.

This patch does the following with the platform specific default_idle()
functions on different architectures:
- remove the unused function:
  - parisc
  - sparc64
- make the needlessly global function static:
  - arm
  - h8300
  - m68k
  - m68knommu
  - s390
  - v850
  - x86_64
- add a prototype in asm/system.h:
  - cris
  - i386
  - ia64

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Patrick Mochel <mochel@digitalimplant.org>
Acked-by: Kyle McMartin <kyle@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-24 07:33:21 -08:00
Tony Luck
dc5cdd8ec1 Pull mca-cleanup into release branch 2006-03-21 08:22:39 -08:00
Tony Luck
581249966f Pull delete-sigdelayed into release branch 2006-03-21 08:17:38 -08:00
Tony Luck
536ea4e419 Pull bsp-removal into release branch 2006-03-21 08:16:21 -08:00
Christoph Lameter
d8117ce5a6 [IA64] Fix race in the accessed/dirty bit handlers
A pte may be zapped by the swapper, exiting process, unmapping or page
migration while the accessed or dirty bit handers are about to run. In that
case the accessed bit or dirty is set on an zeroed pte which leads the VM to
conclude that this is a swap pte. This may lead to

- Messages from the vm like

swap_free: Bad swap file entry 4000000000000000

- Processes being aborted

swap_dup: Bad swap file entry 4000000000000000
VM: killing process ....

Page migration is particular suitable for the creation of this race since
it needs to remove and restore page table entries.

The fix here is to check for the present bit and simply not update
the pte if the page is not present anymore. If the page is not present
then the fault handler should run next which will take care of the problem
by bringing the page back and then mark the page dirty or move it onto the
active list.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-03-08 16:07:55 -08:00
Russ Anderson
e1c48554ae [IA64] mca recovery return value when no bus check
When there is no bus check, the return code should be failure, not success.

Signed-off-by: Russ Anderson (rja@sgi.com)
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-03-07 15:40:06 -08:00
Bjorn Helgaas
6c5e62159c [IA64] don't report !sn2 or !summit hardware as an error
This stuff is all in the generic ia64 kernel, and the new initcall error
reporting complains about them.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-03-07 15:26:49 -08:00
Russ Anderson
ea0e92a613 [IA64] Increase severity of MCA recovery messages
The MCA recovery messages are currently KERN_DEBUG,
so they don't show up in /var/log/messages (by default).
Increase the severity to KERN_ERR, for the initial
message (and also add the physical address to this
message). Leave the successful isolation message as
KERN_DEBUG, but increase the severity when isolation
fails to KERN_CRIT.

[Russ' patch made these all KERN_CRIT]

Signed-off-by: Russ Anderson (rja@sgi.com)
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-03-07 15:23:25 -08:00
Jes Sorensen
d2b176ed87 [IA64] sysctl option to silence unaligned trap warnings
Allow sysadmin to disable all warnings about userland apps
making unaligned accesses by using:
 # echo 1 > /proc/sys/kernel/ignore-unaligned-usertrap
Rather than having to use prctl on a process by process basis.

Default behaivour leaves the warnings enabled.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-28 09:42:23 -08:00
Ken Chen
c8c1635faa [IA64] cleanup in fsys.S
beautify coding style for zeroing end of fsyscall_table entries.
Remove misleading __NR_syscall_last and add more comments.
Drop (now unneeded) "guard against failure to increase NR_syscalls"

Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-28 08:53:32 -08:00
Tony Luck
e963701a76 [IA64] die_if_kernel() can return
arch/ia64/kernel/unaligned.c erroneously marked die_if_kernel()
with a "noreturn" attribute ... which is silly (it returns whenever
the argument regs say that the fault happened in user mode, as one
might expect given the "if_kernel" part of its name!).  Thanks to
Alan and Gareth for pointing this out.

Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-27 16:18:58 -08:00
Zhang, Yanmin
5d1a88af82 [IA64] Delete a redundant instruction in unaligned_access
unaligned_access does fetch cr.ipsr, then calls
dispatch_unaligned_handler, but dispatch_unaligned_handler fetches
cr.ipsr again, so delete the first one.

Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-27 15:12:42 -08:00
Ashok Raj
8f8b1138fc [IA64] Count disabled cpus as potential hot-pluggable CPUs
Minor updates to earlier patch.
- Added to documentation to add ia64 as well.
- Minor clarification on how to use disabled cpus
- used plain max instead of max_t per Andew Morton.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-16 14:10:50 -08:00
Jack Steiner
6f6d75825d [IA64] Missing check for TIF_WORK if trace/audit enabled
It appears that if auditing is enabled, the kernel fails to
check for pending signals before returning to user mode.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Acked-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-16 10:20:08 -08:00
Tony Luck
72166c35f0 Pull fix-cpu-possible-map into release branch 2006-02-15 15:17:57 -08:00
Horms
b05de01ae1 [IA64] support panic_on_oops sysctl
Trivial port of this feature from i386
As it stands, panic_on_oops but does nothing on ia64

Signed-Off-By: Horms <horms@verge.net.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-15 15:16:50 -08:00
hawkes@sgi.com
defbb2c929 [IA64] ia64: simplify and fix udelay()
The original ia64 udelay() was simple, but flawed for platforms without
synchronized ITCs:  a preemption and migration to another CPU during the
while-loop likely resulted in too-early termination or very, very
lengthy looping.

The first fix (now in 2.6.15) broke the delay loop into smaller,
non-preemptible chunks, reenabling preemption between the chunks.  This
fix is flawed in that the total udelay is computed to be the sum of just
the non-premptible while-loop pieces, i.e., not counting the time spent
in the interim preemptible periods.  If an interrupt or a migration
occurs during one of these interim periods, then that time is invisible
and only serves to lengthen the effective udelay().

This new fix backs out the current flawed fix and returns to a simple
udelay(), fully preemptible and interruptible.  It implements two simple
alternative udelay() routines:  one a default generic version that uses
ia64_get_itc(), and the other an sn-specific version that uses that
platform's RTC.

Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-15 13:37:04 -08:00
Andreas Schwab
50d8e59038 [IA64] Remove duplicate EXPORT_SYMBOLs
Remove symbol exports from ia64_ksyms.c that are already exported in
lib/string.c.

Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-15 13:23:32 -08:00
Ashok Raj
a6b14fa6fd [IA64] Count disabled cpus as potential hot-pluggable CPUs
Have a facility to account for potentially hot-pluggable CPUs. ACPI doesnt
give a determinstic method to find hot-pluggable CPUs. Hence we use 2 methods
to assist.

- BIOS can mark potentially hot-pluggable CPUs as disabled in the MADT tables.
- User can specify the number of hot-pluggable CPUs via parameter
  additional_cpus=X

The option is enabled only if ACPI_CONFIG_HOTPLUG_CPU=y which enables the
physical hotplug option. Without which user can still use logical onlining
and offlining of CPUs by enabling CONFIG_HOTPLUG_CPU=y

Adds more bits to cpu_possible_map for potentially hot-pluggable cpus.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-14 15:37:58 -08:00
Ashok Raj
69aa234b91 [IA64] Dont set NR_CPUS for cpu_possible_map when CPU hotplug is enabled.
Do not set cpu_possible_map for NR_CPUS when ACPI_CONFIG_HOTPLUG_CPU is set.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-14 15:35:10 -08:00
Tony Luck
65b78722ce Pull new-syscalls into release branch 2006-02-09 14:43:58 -08:00
Hidetoshi Seto
a947464617 [IA64] mca_drv: Add minstate validation
MCA driver can cause panic if kernel gets a state info with no minstate.
This patch adds minstate validation before handling it.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-09 14:42:55 -08:00
Janak Desai
9621a4ef8a [IA64] unshare system call registration for ia64
Registers system call for the ia64 architecture.

Reserves space for ppoll and pselect, and adds unshare at system
call number 1296.

Signed-off-by: Janak Desai <janak@us.ibm.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-08 15:43:38 -08:00
Keith Owens
2730c9295a [IA64] MCA: remove obsolete ifdef
No platform in the community tree uses PLATFORM_MCA_HANDLERS, remove
the references.

Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-08 12:02:07 -08:00
Keith Owens
e9ac054daa [IA64] MCA: update MCA comm field for user space tasks
Update the comm field on the MCA handler for user tasks as well as for
verified kernel tasks.  This helps to identify the task that was
running when the MCA occurred.

Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-08 12:01:41 -08:00
Keith Owens
9336b0836b [IA64] MCA: print messages in MCA handler
Print a message identifying the monarch MCA handler.  Print a summary
of the status of the slave MCA cpus.

Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-08 11:59:23 -08:00
Tony Luck
d6e56a2a08 [IA64] Fix CONFIG_PRINTK_TIME
There were two problems with enabling the PRINTK_TIME config
option:
1) The first calls to printk() occur before per-cpu data virtual
address is pinned into the TLB, so sched_clock() can fault.
2) sched_clock() is based on ar.itc, which may not be synchronized
across cpus.

Ken Chen started this patch, Tony Luck tinkered with it, and Jes
Sorensen perfected it.

Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-07 15:25:57 -08:00
Zou Nan hai
9d78f43d1f [IA64] Fix wrong use of memparse in efi.c
The check of (end != cp) after memparse in efi.c looks wrong to me.
The result is that we can't use mem= and max_addr= kernel parameter at
the same time.

The following patch removed the check just like other arches do.

Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-07 14:13:09 -08:00
Zou Nan hai
ecdd5dabd3 [IA64] Fix a possible buffer overflow in efi.c
Make sure to save space for the trailing '\0'.

Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-07 10:59:37 -08:00
Linus Torvalds
c03296a868 Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6 2006-02-06 15:46:39 -08:00
Chen, Kenneth W
9ed2ad8648 [IA64] add syscall entry for *at()
Wire up the ia64 syscalls for *at() functions.

Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-06 10:42:46 -08:00
Zhang, Yanmin
69dcc99199 [PATCH] Export cpu topology in sysfs
The patch implements cpu topology exportation by sysfs.

Items (attributes) are similar to /proc/cpuinfo.

1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:
	represent the physical package id of  cpu X;
2) /sys/devices/system/cpu/cpuX/topology/core_id:
	represent the cpu core id to cpu X;
3) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
	represent the thread siblings to cpu X in the same core;
4) /sys/devices/system/cpu/cpuX/topology/core_siblings:
	represent the thread siblings to cpu X in the same physical package;

To implement it in an architecture-neutral way, a new source file,
driver/base/topology.c, is to export the 5 attributes.

If one architecture wants to support this feature, it just needs to
implement 4 defines, typically in file include/asm-XXX/topology.h.
The 4 defines are:
#define topology_physical_package_id(cpu)
#define topology_core_id(cpu)
#define topology_thread_siblings(cpu)
#define topology_core_siblings(cpu)

The type of **_id is int.
The type of siblings is cpumask_t.

To be consistent on all architectures, the 4 attributes should have
deafult values if their values are unavailable. Below is the rule.

1) physical_package_id: If cpu has no physical package id, -1 is the
default value.

2) core_id: If cpu doesn't support multi-core, its core id is 0.

3) thread_siblings: Just include itself, if the cpu doesn't support
HT/multi-thread.

4) core_siblings: Just include itself, if the cpu doesn't support
multi-core and HT/Multi-thread.

So be careful when declaring the 4 defines in include/asm-XXX/topology.h.

If an attribute isn't defined on an architecture, it won't be exported.

Thank Nathan, Greg, Andi, Paul and Venki.

The patch provides defines for i386/x86_64/ia64.

Signed-off-by: Zhang, Yanmin <yanmin.zhang@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-03 08:32:09 -08:00
Bjorn Helgaas
a58786917c [IA64] avoid broken SAL_CACHE_FLUSH implementations
If SAL_CACHE_FLUSH drops interrupts, complain about it and fall back to
using PAL_CACHE_FLUSH instead.

This is to work around a defect in HP rx5670 firmware: when an interrupt
occurs during SAL_CACHE_FLUSH, SAL drops the interrupt but leaves it marked
"in-service", which leaves the interrupt (and others of equal or lower
priority) masked.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-02-02 13:25:54 -08:00
Linus Torvalds
59ed2f59e4 Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2006-02-01 22:06:15 -08:00
Keith Owens
b0a06623dc [IA64] Delete MCA/INIT sigdelayed code
The only user of the MCA/INIT sigdelayed code (SGI's I/O probing) has
moved from the kernel into SAL.  Delete the MCA/INIT sigdelayed code.

Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-26 13:23:27 -08:00
Len Brown
9fdb62af92 [ACPI] merge 3549 4320 4485 4588 4980 5483 5651 acpica asus fops pnpacpi branches into release
Signed-off-by: Len Brown <len.brown@intel.com>
2006-01-24 17:52:48 -05:00
Jack Steiner
79c83bd15a [IA64] Scaling fix for simultaneous unaligned accesses
Eliminate a hot shared cacheline that occurs if multiple cpus are
taking unaligned exceptions.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-24 14:39:50 -08:00
Keith Owens
2a792058c3 [IA64] Set the correct default OS status in the MCA handler
sos->os_status is set to a default value of IA64_MCA_COLD_BOOT for an
MCA, but then is incorrectly overwritten with IA64_MCA_SAME_CONTEXT (0).
This makes SAL think that all MCAs have been recovered.

Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-24 11:50:07 -08:00
Ashok Raj
b88e926584 [IA64] Fix UP build with BSP removal support.
Causes undefined force_cpei_retarget defined in arch/ia64/kernel/smpboot.c
Push the unneeded code inside #ifdef CONFIG_HOTPLUG_CPU.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-19 16:18:47 -08:00
John Hawkes
386d1d50c8 [IA64] eliminate softlockup warning
Fix an unnecessary softlockup watchdog warning in the ia64
uncached_build_memmap() that occurs occasionally at 256p and always at
512p.  The problem occurs at boot time.

Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-19 11:18:25 -08:00
Jes Sorensen
60f1c4443c [IA64] sem2mutex: arch/ia64/kernel/perfmon.c
Migrate perfmon from using an old semaphore to a completion handler.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-19 11:17:56 -08:00
Stephane Eranian
9179cb6578 [IA64] Perfmon for Montecito
Add Montecito PMU description table for perfmon2

Signed-off-by: Stephane Eranian <eranian@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-16 10:31:44 -08:00
Zhang Yanmin
d3ef1f5aaf [IA64] prevent accidental modification of args in jprobe handler
When jprobe is hit, the function parameters of the original function
should be saved before jprobe handler is executed, and restored it after
jprobe handler is executed, because jprobe handler might change the
register values due to tail call optimization by the gcc.

Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-13 14:45:21 -08:00
Keith Owens
e026cca0f2 [IA64] Add hotplug cpu to salinfo.c, replace semaphore with mutex
Add hotplug cpu support to salinfo.c.

The cpu_event field is a cpumask so use the cpu_* macros consistently,
replacing the existing mixture of cpu_* and *_bit macros.

Instead of counting the number of outstanding events in a semaphore and
trying to track that count over user space context, interrupt context,
non-maskable interrupt context and cpu hotplug, replace the semaphore
with a test for "any bits set" combined with a mutex.

Modify the locking to make the test for "work to do" an atomic
operation.

Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-13 14:22:35 -08:00
Jason Uhlenkott
15029285dc [IA64] Handle debug traps in fsys mode
We need to handle debug traps in fsys mode non-fatally.  They can
happen now that we have fsyscalls which contain probe instructions.

Signed-off-by: Jason Uhlenkott <jasonuhl@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-13 14:16:08 -08:00
Francois Wellenrieter
8a4b7b6f18 [IA64] Fix conversion of pal_min_state physical address
On return from INIT handler we must convert the address of the
minstate area from a kernel virtual uncached address (0xC...)
to physical uncached (0x8...).  A typo (or thinko?) in the code
converted to physical cached.

Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-13 14:01:01 -08:00
Tony Luck
7ae69d2aa4 [IA64] Add stub entry to fsys.S for sys_migrate_pages
When this new syscall was added to ia64 in commit

  39743889aa

fsys.S was forgotten.  Add a ".data8 0" there to keep
it in step.  [Reported by Stephane Eranian]

Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-13 10:03:58 -08:00
Al Viro
6450578f32 [PATCH] ia64: task_pt_regs()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12 09:08:58 -08:00
Al Viro
ab03591db1 [PATCH] ia64: task_thread_info()
on ia64 thread_info is at the constant offset from task_struct and stack
is embedded into the same beast.  Set __HAVE_THREAD_FUNCTIONS, made
task_thread_info() just add a constant.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12 09:08:58 -08:00
akpm@osdl.org
198e2f1811 [PATCH] scheduler cache-hot-autodetect
)

From: Ingo Molnar <mingo@elte.hu>

This is the latest version of the scheduler cache-hot-auto-tune patch.

The first problem was that detection time scaled with O(N^2), which is
unacceptable on larger SMP and NUMA systems. To solve this:

- I've added a 'domain distance' function, which is used to cache
  measurement results. Each distance is only measured once. This means
  that e.g. on NUMA distances of 0, 1 and 2 might be measured, on HT
  distances 0 and 1, and on SMP distance 0 is measured. The code walks
  the domain tree to determine the distance, so it automatically follows
  whatever hierarchy an architecture sets up. This cuts down on the boot
  time significantly and removes the O(N^2) limit. The only assumption
  is that migration costs can be expressed as a function of domain
  distance - this covers the overwhelming majority of existing systems,
  and is a good guess even for more assymetric systems.

  [ People hacking systems that have assymetries that break this
    assumption (e.g. different CPU speeds) should experiment a bit with
    the cpu_distance() function. Adding a ->migration_distance factor to
    the domain structure would be one possible solution - but lets first
    see the problem systems, if they exist at all. Lets not overdesign. ]

Another problem was that only a single cache-size was used for measuring
the cost of migration, and most architectures didnt set that variable
up. Furthermore, a single cache-size does not fit NUMA hierarchies with
L3 caches and does not fit HT setups, where different CPUs will often
have different 'effective cache sizes'. To solve this problem:

- Instead of relying on a single cache-size provided by the platform and
  sticking to it, the code now auto-detects the 'effective migration
  cost' between two measured CPUs, via iterating through a wide range of
  cachesizes. The code searches for the maximum migration cost, which
  occurs when the working set of the test-workload falls just below the
  'effective cache size'. I.e. real-life optimized search is done for
  the maximum migration cost, between two real CPUs.

  This, amongst other things, has the positive effect hat if e.g. two
  CPUs share a L2/L3 cache, a different (and accurate) migration cost
  will be found than between two CPUs on the same system that dont share
  any caches.

(The reliable measurement of migration costs is tricky - see the source
for details.)

Furthermore i've added various boot-time options to override/tune
migration behavior.

Firstly, there's a blanket override for autodetection:

	migration_cost=1000,2000,3000

will override the depth 0/1/2 values with 1msec/2msec/3msec values.

Secondly, there's a global factor that can be used to increase (or
decrease) the autodetected values:

	migration_factor=120

will increase the autodetected values by 20%. This option is useful to
tune things in a workload-dependent way - e.g. if a workload is
cache-insensitive then CPU utilization can be maximized by specifying
migration_factor=0.

I've tested the autodetection code quite extensively on x86, on 3
P3/Xeon/2MB, and the autodetected values look pretty good:

Dual Celeron (128K L2 cache):

 ---------------------
 migration cost matrix (max_cache_size: 131072, cpu: 467 MHz):
 ---------------------
           [00]    [01]
 [00]:     -     1.7(1)
 [01]:   1.7(1)    -
 ---------------------
 cacheflush times [2]: 0.0 (0) 1.7 (1784008)
 ---------------------

Here the slow memory subsystem dominates system performance, and even
though caches are small, the migration cost is 1.7 msecs.

Dual HT P4 (512K L2 cache):

 ---------------------
 migration cost matrix (max_cache_size: 524288, cpu: 2379 MHz):
 ---------------------
           [00]    [01]    [02]    [03]
 [00]:     -     0.4(1)  0.0(0)  0.4(1)
 [01]:   0.4(1)    -     0.4(1)  0.0(0)
 [02]:   0.0(0)  0.4(1)    -     0.4(1)
 [03]:   0.4(1)  0.0(0)  0.4(1)    -
 ---------------------
 cacheflush times [2]: 0.0 (33900) 0.4 (448514)
 ---------------------

Here it can be seen that there is no migration cost between two HT
siblings (CPU#0/2 and CPU#1/3 are separate physical CPUs). A fast memory
system makes inter-physical-CPU migration pretty cheap: 0.4 msecs.

8-way P3/Xeon [2MB L2 cache]:

 ---------------------
 migration cost matrix (max_cache_size: 2097152, cpu: 700 MHz):
 ---------------------
           [00]    [01]    [02]    [03]    [04]    [05]    [06]    [07]
 [00]:     -    19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1)
 [01]:  19.2(1)    -    19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1)
 [02]:  19.2(1) 19.2(1)    -    19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1)
 [03]:  19.2(1) 19.2(1) 19.2(1)    -    19.2(1) 19.2(1) 19.2(1) 19.2(1)
 [04]:  19.2(1) 19.2(1) 19.2(1) 19.2(1)    -    19.2(1) 19.2(1) 19.2(1)
 [05]:  19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1)    -    19.2(1) 19.2(1)
 [06]:  19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1)    -    19.2(1)
 [07]:  19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1)    -
 ---------------------
 cacheflush times [2]: 0.0 (0) 19.2 (19281756)
 ---------------------

This one has huge caches and a relatively slow memory subsystem - so the
migration cost is 19 msecs.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Cc: <wilder@us.ibm.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12 09:08:50 -08:00