Commit 83ce4009 did the following change
If the TSC is constant and non-stop, also set it reliable.
But, there seems to be few systems that will end up with TSC warp across
sockets, depending on how the cpus come out of reset. Skipping TSC sync
test on such systems may result in time inconsistency later.
So, reenable TSC sync test even on constant and non-stop TSC systems.
Set, sched_clock_stable to 1 by default and reset it in
mark_tsc_unstable, if TSC sync fails.
This change still gives perf benefit mentioned in 83ce4009 for systems
where TSC is reliable.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20091217202702.GA18015@linux-os.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
When there are a large number of processors in a system, there
is an excessive amount of messages sent to the system console.
It's estimated that with 4096 processors in a system, and the
console baudrate set to 56K, the startup messages will take
about 84 minutes to clear the serial port.
This set of patches limits the number of repetitious messages
which contain no additional information. Much of this information
is obtainable from the /proc and /sysfs. Some of the messages
are also sent to the kernel log buffer as KERN_DEBUG messages so
dmesg can be used to examine more closely any details specific to
a problem.
The new cpu bootup sequence for system_state == SYSTEM_BOOTING:
Booting Node 0, Processors #1#2#3#4#5#6#7 Ok.
Booting Node 1, Processors #8#9#10#11#12#13#14#15 Ok.
...
Booting Node 3, Processors #56#57#58#59#60#61#62#63 Ok.
Brought up 64 CPUs
After the system is running, a single line boot message is displayed
when CPU's are hotplugged on:
Booting Node %d Processor %d APIC 0x%x
Status of the following lines:
CPU: Physical Processor ID: printed once (for boot cpu)
CPU: Processor Core ID: printed once (for boot cpu)
CPU: Hyper-Threading is disabled printed once (for boot cpu)
CPU: Thermal monitoring enabled printed once (for boot cpu)
CPU %d/0x%x -> Node %d: removed
CPU %d is now offline: only if system_state == RUNNING
Initializing CPU#%d: KERN_DEBUG
Signed-off-by: Mike Travis <travis@sgi.com>
LKML-Reference: <4B219E28.8080601@sgi.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
CPU to node mapping is set via the following sequence:
1. numa_init_array(): Set up roundrobin from cpu to online node
2. init_cpu_to_node(): Set that according to apicid_to_node[]
according to srat only handle the node that
is online, and leave other cpu on node
without ram (aka not online) to still
roundrobin.
3. later call srat_detect_node for Intel/AMD, will use first_online
node or nearby node.
Problem is that setup_per_cpu_areas() is not called between 2 and 3,
the per_cpu for cpu on node with ram is on different node, and could
put that on node with two hops away.
So try to optimize this and add find_near_online_node() and call
init_cpu_to_node().
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B07A739.3030104@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move the APERFMPERF capacility into a X86_FEATURE flag so that it
can be used outside of the acpi cpufreq driver.
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: cpufreq@vger.kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
No code changes except printk levels (although some of the K6
mtrr code might be clearer if there were a few as would
splitting out some of the intel cache code).
Signed-off-by: Alan Cox <alan@linux.intel.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The hooks that we modify are:
- Page fault handler (to handle kmemcheck faults)
- Debug exception handler (to hide pages after single-stepping
the instruction that caused the page fault)
Also redefine memset() to use the optimized version if kmemcheck is
enabled.
(Thanks to Pekka Enberg for minimizing the impact on the page fault
handler.)
As kmemcheck doesn't handle MMX/SSE instructions (yet), we also disable
the optimized xor code, and rely instead on the generic C implementation
in order to avoid false-positive warnings.
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
[whitespace fixlet]
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
should not call that if apic is disabled.
[ Impact: fix crash on certain UP configs ]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
LKML-Reference: <4A09CCBB.2000306@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: 32/64-bit consolidation
In a first step, this allows fixing phys_addr_valid() for PAE (which
until now reported all addresses to be valid). Subsequently, this will
also allow simplifying some MTRR handling code.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B9101E.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: debuggability and micro-optimization
Putting whatever is possible into the (final) .rodata section increases
the likelihood of catching memory corruption bugs early, and reduces
false cache line sharing.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B90961.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup and code size reduction on 64-bit
This code is only applied to Intel Pentium and AMD K7 32-bit cpus.
Move those checks to intel_init()/amd_init() for 32-bit
so 64-bit will not build this code.
Also change to use cpu_index check to see if we need to emit warning.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <49B377D2.8030108@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If the TSC is constant and non-stop, also set it reliable.
(We will turn this off in DMI quirks for multi-chassis systems)
The performance number on a 16-way Nehalem system running
32 tasks that context-switch between each other is significant:
sched_clock_stable=0 sched_clock_stable=1
.................... ....................
22.456925 million/sec 24.306972 million/sec [+8.2%]
lmbench's "lat_ctx -s 0 2" goes from 0.63 microseconds to
0.59 microseconds - a 6.7% increase in context-switching
performance.
Perfstat of 1 million pipe context switches between two tasks:
Performance counter stats for './pipe-test-1m':
[before] [after]
............ ............
37621.421089 36436.848378 task clock ticks (msecs)
0 0 CPU migrations (events)
2000274 2000189 context switches (events)
194 193 pagefaults (events)
8433799643 8171016416 CPU cycles (events) -3.21%
8370133368 8180999694 instructions (events) -2.31%
4158565 3895941 cache references (events) -6.74%
44312 46264 cache misses (events)
2349.287976 2279.362465 wall-time (msecs) -3.06%
The speedup comes straight from the reduction in the instruction
count. sched_clock_cpu() got simpler and the whole workload thus
executes faster.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
For Intel 7400 series CPUs, the recommendation is to use a clflush on the
monitored address just before monitor and mwait pair [1].
This clflush makes sure that there are no false wakeups from mwait when the
monitored address was recently written to.
[1] "MONITOR/MWAIT Recommendations for Intel Xeon Processor 7400 series"
section in specification update document of 7400 series
http://download.intel.com/design/xeon/specupdt/32033601.pdf
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: re-enable CPUID unmasking on affected processors
As far as I am capable of discerning from the documentation,
MSR_IA32_MISC_ENABLE should be available for all family 0xf CPUs, as
well as family 6 for model >= 0xd (newer Pentium M).
The documentation on this isn't ideal, so we need to be on the lookout
for errors, still.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: fix boot hang on pre-model-15 Intel CPUs
rdmsrl_safe() does not work in very early bootup code yet, because we
dont have the pagefault handler installed yet so exception section
does not get parsed. rdmsr_safe() will just crash and hang the bootup.
So limit the MSR_IA32_MISC_ENABLE MSR read to those CPU types that
support it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Cleanup
When PAT was originally introduced, it was handled specially for a few
reasons:
- PAT bugs are hard to track down, so we wanted to maintain a
whitelist of CPUs.
- The i386 and x86-64 CPUID code was not yet unified.
Both of these are now obsolete, so handle PAT like any other features,
including ordinary feature blacklisting due to known bugs.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Impact: Fixes crashes with misconfigured BIOSes on XSAVE hardware
Avuton Olrich reported early boot crashes with v2.6.28 and
bisected it down to dc1e35c6e9
("x86, xsave: enable xsave/xrstor on cpus with xsave support").
If the CPUID limit bit in MSR_IA32_MISC_ENABLE is set, clear it to
make all CPUID information available. This is required for some
features to work, in particular XSAVE.
Reported-and-bisected-by: Avuton Olrich <avuton@gmail.com>
Tested-by: Avuton Olrich <avuton@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Impact: fix wrong cache sharing detection on platforms supporting > 8 bit apicid's
In the presence of extended topology eumeration leaf 0xb provided
by cpuid, 32bit extended initial_apicid in cpuinfo_x86 struct will be
updated by detect_extended_topology(). At this instance, we should also
reinit the apicid (which could also potentially be extended to 32bit).
With out this there will potentially be duplicate apicid's populated in the
per cpu's cpuinfo_x86 struct, resulting in wrong cache sharing topology etc
detected by init_intel_cacheinfo().
Reported-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Impact: reward non-stop TSCs with good TSC-based clocksources, etc.
Add support for CPUID_0x80000007_Bit8 on Intel CPUs as well. This bit means
that the TSC is invariant with C/P/T states and always runs at constant
frequency.
With Intel CPUs, we have 3 classes
* CPUs where TSC runs at constant rate and does not stop n C-states
* CPUs where TSC runs at constant rate, but will stop in deep C-states
* CPUs where TSC rate will vary based on P/T-states and TSC will stop in deep
C-states.
To cover these 3, one feature bit (CONSTANT_TSC) is not enough. So, add a
second bit (NONSTOP_TSC). CONSTANT_TSC indicates that the TSC runs at
constant frequency irrespective of P/T-states, and NONSTOP_TSC indicates
that TSC does not stop in deep C-states.
CPUID_0x8000000_Bit8 indicates both these feature bit can be set.
We still have CONSTANT_TSC _set_ and NONSTOP_TSC _not_set_ on some older Intel
CPUs, based on model checks. We can use TSC on such CPUs for time, as long as
those CPUs do not support/enter deep C-states.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Move the BTS bits from ptrace.c into ds.c.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: widen BTS/PEBS ptrace enablement to more CPU models
Move BTS initialisation out of an #ifdef CONFIG_X86_64 guard.
Assume core2 BTS and DS layout for future models of family 6 processors.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The hardware virtualization technology evolves very fast. But currently
it's hard to tell if your CPU support a certain kind of HW technology
without digging into the source code.
The patch add a new catagory in "flags" under /proc/cpuinfo. Now "flags"
can indicate the (important) HW virtulization features the CPU supported
as well.
Current implementation just cover Intel VMX side.
Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
consolidate the code some more.
No change in functionality intended.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
1. add c_x86_vendor into cpu_dev
2. change cpu_devs to static
3. check c_x86_vendor before put that cpu_dev into array
4. remove alignment for 64bit
5. order the sequence in cpu_devs according to link sequence...
so could put intel at first, then amd...
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
cpuid leaf 0xb provides extended topology enumeration. This interface provides
the 32-bit x2APIC id of the logical processor and it also provides a new
mechanism to detect SMT and core siblings (which provides increased
addressability).
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/cpu/intel.c defines a few fallback functions
(cmpxchg_*()) that are used when the CPU doesn't support cmpxchg
and/or cmpxchg64 natively. However, while defined in an Intel-specific
file, these functions are also used for CPUs from other vendors when
they don't support cmpxchg and/or cmpxchg64. This breaks the
compilation when support for Intel CPUs is disabled.
This patch moves these functions to a new
arch/x86/kernel/cpu/cmpxchg.c file, unconditionally compiled when
X86_32 is enabled.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: michael@free-electrons.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
movsl_mask is currently defined in arch/x86/kernel/cpu/intel.c, which
contains code specific to Intel CPUs. However, movsl_mask is used in
the non-CPU specific code in arch/x86/lib/usercopy_32.c, which breaks
the compilation when support for Intel CPUs is compiled out.
This patch solves this problem by moving movsl_mask's definition close
to its users in arch/x86/lib/usercopy_32.c.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: michael@free-electrons.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Use alternatives to select the workaround for the 11AP Pentium erratum
for the affected steppings on the fly rather than build time. Remove the
X86_GOOD_APIC configuration option and replace all the calls to
apic_write_around() with plain apic_write(), protecting accesses to the
ESR as appropriate due to the 3AP Pentium erratum. Remove
apic_read_around() and all its invocations altogether as not needed.
Remove apic_write_atomic() and all its implementing backends. The use of
ASM_OUTPUT2() is not strictly needed for input constraints, but I have
used it for readability's sake.
I had the feeling no one else was brave enough to do it, so I went ahead
and here it is. Verified by checking the generated assembly and tested
with both a 32-bit and a 64-bit configuration, also with the 11AP
"feature" forced on and verified with gdb on /proc/kcore to work as
expected (as an 11AP machines are quite hard to get hands on these days).
Some script complained about the use of "volatile", but apic_write() needs
it for the same reason and is effectively a replacement for writel(), so I
have disregarded it.
I am not sure what the policy wrt defconfig files is, they are generated
and there is risk of a conflict resulting from an unrelated change, so I
have left changes to them out. The option will get removed from them at
the next run.
Some testing with machines other than mine will be needed to avoid some
stupid mistake, but despite its volume, the change is not really that
intrusive, so I am fairly confident that because it works for me, it will
everywhere.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
got this on a test-system:
calling numaq_tsc_disable+0x0/0x39
NUMAQ: disabling TSC
initcall numaq_tsc_disable+0x0/0x39 returned 0 after 0 msecs
that's because we should not be using arch_initcall to call numaq_tsc_disable.
need to call it in setup_arch before time_init()/tsc_init()
and call it in init_intel() to make the cpu feature bits right.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Polish the ds.h interface and add support for PEBS.
Ds.c is meant to be the resource allocator for per-thread and per-cpu
BTS and PEBS recording.
It is used by ptrace/utrace to provide execution tracing of debugged tasks.
It will be used by profilers (e.g. perfmon2).
It may be used by kernel debuggers to provide a kernel execution trace.
Changes in detail:
- guard DS and ptrace by CONFIG macros
- separate DS and BTS more clearly
- simplify field accesses
- add functions to manage PEBS buffers
- add simple protection/allocation mechanism
- added support for Atom
Opens:
- buffer overflow handling
Currently, only circular buffers are supported. This is all we need
for debugging. Profilers would want an overflow notification.
This is planned to be added when perfmon2 is made to use the ds.h
interface.
- utrace intermediate layer
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Replace the hardcoded list of initialization functions for each CPU
vendor by a list in an ELF section, which is read at initialization in
arch/x86/kernel/cpu/cpu.c to fill the cpu_devs[] array. The ELF
section, named .x86cpuvendor.init, is reclaimed after boot, and
contains entries of type "struct cpu_vendor_dev" which associates a
vendor number with a pointer to a "struct cpu_dev" structure.
This first modification allows to remove all the VENDOR_init_cpu()
functions.
This patch also removes the hardcoded calls to early_init_amd() and
early_init_intel(). Instead, we add a "c_early_init" member to the
cpu_dev structure, which is then called if not NULL by the generic CPU
initialization code. Unfortunately, in early_cpu_detect(), this_cpu is
not yet set, so we have to use the cpu_devs[] array directly.
This patch is part of the Linux Tiny project, and is needed for
further patch that will allow to disable compilation of unused CPU
support code.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
