The pmu_active test is based on the values of PSR.up. THIS IS THE PROBLEM as
it does not take into account the lazy restore logic which is as follow (simplified):
context switch out:
save PMDs
clear psr.up
release ownership
context switch in:
if (ctx->last_cpu == smp_processor_id() && ctx->cpu_activation == cpu_activation) {
set psr.up
return
}
restore PMD
restore PMC
ctx->last_cpu = smp_processor_id();
ctx->activation = ++cpu_activation;
set psr.up
The key here is that on context switch out, we clear psr.up and on context switch in
we check if nobody else used the PMU on that processor since last time we came. In
that case, we assume the PMD/PMC are ours and we simply reactivate.
The Caliper problem is that between the moment we context switch out and the moment we
come back, nobody effectively used the PMU BUT the processor went idle. Normally this
would have no incidence but PAL_HALT does alter the PMU registers. In default_idle(),
the test on psr.up is not strong enough to cover this case and we go into PAL which
trashed the PMU resgisters. When we come back we falsely assume that this is our state
yet it is corrupted. Very nasty indeed.
To avoid the problem it is necessary to forbid going to PAL_HALT as soon as perfmon
installs some valid state in the PMU registers. This happens with an application
attaches a context to a thread or CPU. It is not enough to check the psr/dcr bits.
Hence I propose the attached patch. It adds a callback in process.c to modify the
condition to enter PAL on idle. Basically, now it is conditional to pal_halt=1 AND
perfmon saying it is okay.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Jack Steiner uncovered some opportunities for improvement in
the MCA recovery code.
1) Set bsp to save registers on the kernel stack.
2) Disable interrupts while in the MCA recovery code.
3) Change the way the user process is killed, to avoid
a panic in schedule.
Testing shows that these changes make the recovery code much
more reliable with the 2.6.12 kernel.
Signed-off-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Attached is a patch against David's audit.17 kernel that adds checks
for the TIF_SYSCALL_AUDIT thread flag to the ia64 system call and
signal handling code paths. The patch enables auditing of system
calls set up via fsys_bubble_down, as well as ensuring that
audit_syscall_exit() is called on return from sigreturn.
Neglecting to check for TIF_SYSCALL_AUDIT at these points results in
incorrect information in audit_context, causing frequent system panics
when system call auditing is enabled on an ia64 system.
I have tested this patch and have seen no problems with it.
[Original patch from Amy Griffis ported to current kernel by David Woodhouse]
From: Amy Griffis <amy.griffis@hp.com>
From: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Andi noted that during normal runtime cpu_idle_map is bounced around a lot,
and occassionally at a higher frequency than the timer interrupt wakeup
which we normally exit pm_idle from. So switch to a percpu variable.
I didn't move things to the slow path because it would involve adding
scheduler code to wakeup the idle thread on the cpus we're waiting for.
Signed-off-by: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch simplifies a couple places where we search for _PXM
values in ACPI namespace. Thanks,
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Patch below fixes 3 trivial typos which are caught by the new
assembler (v2.169.90). Please apply.
[Note: fix to memcpy that was also part of this patch was separately
applied from patches by H.J. and Andreas ... so the delta here only
has the other two fixes. -Tony]
Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Convert most of the current code that uses _NSIG directly to instead use
valid_signal(). This avoids gcc -W warnings and off-by-one errors.
Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
vector sharing patch had a typo ... mismatched spin_lock() with
a spin_unlock_irq(). Fix from Kenji Kaneshige.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Rohit and Suresh changed their mind about the order to print things
in /proc/cpuinfo, but didn't include the change in the version of
the patch they sent to me.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Current ia64 linux cannot handle greater than 184 interrupt sources
because of the lack of vectors. The following patch enables ia64 linux
to handle greater than 184 interrupt sources by allowing the same
vector number to be shared by multiple IOSAPIC's RTEs. The design of
this patch is besed on "Intel(R) Itanium(R) Processor Family Interrupt
Architecture Guide".
Even if you don't have a large I/O system, you can see the behavior of
vector sharing by changing IOSAPIC_LAST_DEVICE_VECTOR to fewer value.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Version 3 - rediffed to apply on top of Ashok's hotplug cpu
patch. /proc/cpuinfo output in step with x86.
This is an updated MC/MT identification patch based on the
previous discussions on list.
Add the Multi-core and Multi-threading detection for IPF.
- Add new core and threading related fields in /proc/cpuinfo.
Physical id
Core id
Thread id
Siblings
- setup the cpu_core_map and cpu_sibling_map appropriately
- Handles Hot plug CPU
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Gordon Jin <gordon.jin@intel.com>
Signed-off-by: Rohit Seth <rohit.seth@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Sadly, I goofed in this syscall-tuning patch:
ChangeSet 1.1966.1.40 2005/01/22 13:31:05 davidm@hpl.hp.com
[IA64] Improve ia64_leave_syscall() for McKinley-type cores.
Optimize ia64_leave_syscall() a bit better for McKinley-type cores.
The patch looks big, but that's mostly due to renaming r16/r17 to r2/r3.
Good for a 13 cycle improvement.
The problem is that the size of the physical stacked registers was
loaded into the wrong register (r3 instead of r17). Since r17 by
coincidence always had the value 1, this had the effect of turning
rse_clear_invalid into a no-op. That poses the risk of leaking kernel
state back to user-land and is hence not acceptable.
The fix below is simple, but unfortunately it costs us about 28 cycles
in syscall overhead. ;-(
Unfortunately, there isn't much we can do about that since those
registers have to be cleared one way or another.
--david
Signed-off-by: Tony Luck <tony.luck@intel.com>
- make pfm_sysctl a global such that it is possible
to enable/disable debug printk in sampling formats
using PFM_DEBUG.
- remove unused pfm_debug_var variable
- fix a bug in pfm_handle_work where an BUG_ON() could
be triggered. There is a path where pfm_handle_work()
can be called with interrupts enabled, i.e., when
TIF_NEED_RESCHED is set. The fix correct the masking
and unmasking of interrupts in pfm_handle_work() such
that we restore the interrupt mask as it was upon entry.
signed-off-by: stephane eranian <eranian@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Recently I noticed that clearing ar.ssd/ar.csd right before srlz.d is
causing significant stalling in the syscall path. The patch below
fixes that by moving the register-writes after srlz.d. On a Madison,
this drops break-based getpid() from 241 to 226 cycles (-15 cycles).
Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Detect user space by the unwind frame with predicate PRED_USER_STACK
set, instead of a user space IP. Tighten up the last ditch check for
running off the top of the kernel stack.
Based on a suggestion by David Mosberger, reworked to fit the current
tree. This survives my stress test which used to break 2.6.9 kernels.
Unlike 2.6.11, the stress test now unwinds to the correct point, so
gdb can get the user space registers.
Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Call cpu_relax() in busy-waiting loops of the ITC-syncing code.
Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch is required to support cpu removal for IPF systems. Existing code
just fakes the real offline by keeping it run the idle thread, and polling
for the bit to re-appear in the cpu_state to get out of the idle loop.
For the cpu-offline to work correctly, we need to pass control of this CPU
back to SAL so it can continue in the boot-rendez mode. This gives the
SAL control to not pick this cpu as the monarch processor for global MCA
events, and addition does not wait for this cpu to checkin with SAL
for global MCA events as well. The handoff is implemented as documented in
SAL specification section 3.2.5.1 "OS_BOOT_RENDEZ to SAL return State"
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
