Commit Graph

22 Commits

Author SHA1 Message Date
OGAWA Hirofumi
dbffa47161 [PATCH] PM-Timer: don't use workaround if chipset is not buggy
Current timer_pm.c reads I/O port triple times, in order to avoid the bug
of chipset.  But I/O port is slow.

2.6.16 (pmtmr)
Simple gettimeofday: 3.6532 microseconds

2.6.16+patch (pmtmr)
Simple gettimeofday: 1.4582 microseconds

[if chip is buggy, probably it will be 7us or more in 4.2% of probability.]

This patch adds blacklist of buggy chip, and if chip is not buggy, this
uses fast normal version instead of slow workaround version.

If chip is buggy, warnings "pmtmr is slow".  But sounds like there is gray
zone.  I found the PIIX4 errata, but I couldn't find the ICH4 errata.  But
some motherboard seems to have problem.

So, if we found a ICH4, generate warnings, and use a workaround version.
If user's ICH4 is good, the user can specify the "pmtmr_good" boot
parameter to use fast version.

Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 08:44:37 -08:00
Ravikiran G Thirumalai
68ed0040a8 [PATCH] x86: mark cyc2ns_scale readmostly
This variable is rarely written to.  Mark the variable accordingly.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-22 07:53:55 -08:00
Linus Torvalds
934a3595b3 Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq 2006-02-13 19:10:43 -08:00
Thomas Renninger
9d2725bb81 [CPUFREQ] Check for not initialized freq on cpufreq changes
Test for old_freq equals 0 to insure not to divide by 0:
______________________________________________

Check for not initialized freq on cpufreq changes

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
2006-02-02 16:51:44 -05:00
john stultz
bfaa1deeb9 [PATCH] disable lost tick compensation before TSCs are synced
Avoid lost tick compensation early in boot before the TSCs are
synchronized.  Currently timekeeping is enabled before the TSCs are
synchronized, thus when the TSCs are synched (reset to zero), it appears
that a number of lost ticks have occurred.  This can cause premature expiry
of timers and in extreme cases can cause the soft lockup detection to fire.

This resolves issues reported by Andy Whitcroft as well as bug #5366
reported by Tim Mann.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Acked-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01 08:53:14 -08:00
Larry Finger
bcf0f0d233 [PATCH] fix cpu frequency detection in arch/i386/kernel/timers/timer_tsc.c::recalibrate_cpu_khz()
When we re-calibrate the frequency, it is likely that an interrupt (as for
example the main system clock) will be triggered by the system.  Therefore
the calibration may not be accurate.  This will also provide a fix to bug
#5266.

Many thanks to Larry Finger for helping resolving this issue.

Signed-off-by: Bruno Ducrot <ducrot@poupinou.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:39 -08:00
Tim Mann
7feacd5334 [PATCH] x86: fix cpu_khz with clock=pit
Fix http://bugzilla.kernel.org/show_bug.cgi?id=5546

The cpu_khz global is not initialized and remains 0 if you boot with
clock=pit, even if the processor does have a TSC.  This may have bad
ramifications since the variable is used in various places scattered around
the kernel, though I didn't check them all to see if they can tolerate cpu_khz
= 0.  You can observe the problem by doing "cat /proc/cpuinfo"; the cpu MHz
line says 0.000.

The fix is trivial; call init_cpu_khz() from init_pit(), just as it's called
from the timers/timer_foo.c:init_foo() for other values of foo.

Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-13 18:14:13 -08:00
Mathieu Desnoyers
dacb16b1a0 [PATCH] i386 and x86_64 TSC set_cyc2ns_scale imprecision
I just found out that some precision is unnecessarily lost in the
arch/i386/kernel/timers/timer_tsc.c:set_cyc2ns_scale function.  It uses a
cpu_mhz parameter when it could use a cpu_khz.  In the specific case of an
Intel P4 running at 3001.171 Mhz, the truncation to 3001 Mhz leads to an
imprecision of 19 microseconds per second : this is very sad for a timer with
nearly nanosecond accuracy.

Fix the x86_64 architecture too.

Cc: george anzinger <george@mvista.com>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:11 -08:00
Al Viro
ce3a161e69 [PATCH] useless includes of linux/irq.h in arch/i386
Most of these guys are simply not needed (pulled by other stuff
via asm-i386/hardirq.h).  One that is not entirely useless is hilarious -
arch/i386/oprofile/nmi_timer_int.c includes linux/irq.h... as a way to
get linux/errno.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-26 18:29:50 -07:00
Ravikiran G Thirumalai
6c231b7bab [PATCH] Additions to .data.read_mostly section
Mark variables which are usually accessed for reads with __readmostly.

Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:33 -07:00
Christoph Lameter
c3d8c14145 [PATCH] More __read_mostly variables
Move some more frequently read variables that showed up during some of our
performance tests as sometimes ending up in hot cachelines to the
read_mostly section.

Fix: Move the __read_mostly from before hpet_usec_quotient to follow the
variable like the other uses of __read_mostly.

Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Christoph Lameter <christoph@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:18 -07:00
Shaohua Li
c3c433e4f3 [PATCH] add suspend/resume for timer
The timers lack .suspend/.resume methods.  Because of this, jiffies got a
big compensation after a S3 resume.  And then softlockup watchdog reports
an oops.  This occured with HPET enabled, but it's also possible for other
timers.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05 00:06:18 -07:00
Venkatesh Pallipadi
4116c527ea [PATCH] hpet: use read_timer_tsc only when CPU has TSC
Only use read_timer_tsc only when CPU has TSC.  Thanks to Andrea for
pointing this out.  Should not be issue on any platforms as all recent
systems that has HPET also has CPUs that supports TSC.  The patch is still
required for correctness.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05 00:06:09 -07:00
Christoph Lameter
6c036527a6 [PATCH] mostly_read data section
Add a new section called ".data.read_mostly" for data items that are read
frequently and rarely written to like cpumaps etc.

If these maps are placed in the .data section then these frequenly read
items may end up in cachelines with data is is frequently updated.  In that
case all processors in an SMP system must needlessly reload the cachelines
again and again containing elements of those frequently used variables.

The ability to share these cachelines will allow each cpu in an SMP system
to keep local copies of those shared cachelines thereby optimizing
performance.

Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Shobhit Dayal <shobhit@calsoftinc.com>
Signed-off-by: Christoph Lameter <christoph@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-07 18:23:46 -07:00
Ingo Molnar
306e440daf [PATCH] x86: i8253/i8259A lock cleanup
Introduce proper declarations for i8253_lock and i8259A_lock.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-30 08:45:10 -07:00
Li Shaohua
0bb3184df5 [PATCH] init call cleanup
Trival patch for CPU hotplug.  In CPU identify part, only did cleaup for intel
CPUs.  Need do for other CPUs if they support S3 SMP.

Signed-off-by: Li Shaohua<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:30 -07:00
Shaohua Li
a13db56624 [PATCH] CPU hotplug: fix hpet sectioning
With hpet enabled, cpu hotplug uses some routines marked with __init.

Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:28 -07:00
Andrew Morton
a3a255e744 [PATCH] x86: cpu_khz type fix
x86_64's cpu_khz is unsigned int and there is no reason why x86 needs to use
unsigned long.

So make cpu_khz unsigned int on x86 as well.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 09:45:11 -07:00
Venkatesh Pallipadi
8a9e1b0f56 [PATCH] Platform SMIs and their interferance with tsc based delay calibration
Issue:
Current tsc based delay_calibration can result in significant errors in
loops_per_jiffy count when the platform events like SMIs
(System Management Interrupts that are non-maskable) are present. This could
lead to potential kernel panic(). This issue is becoming more visible with 2.6
kernel (as default HZ is 1000) and on platforms with higher SMI handling
latencies. During the boot time, SMIs are mostly used by BIOS (for things
like legacy keyboard emulation).

Description:
The psuedocode for current delay calibration with tsc based delay looks like
(0) Estimate a value for loops_per_jiffy
(1) While (loops_per_jiffy estimate is accurate enough)
(2)   wait for jiffy transition (jiffy1)
(3)   Note down current tsc (tsc1)
(4)   loop until tsc becomes tsc1 + loops_per_jiffy
(5)   check whether jiffy changed since jiffy1 or not and refine
loops_per_jiffy estimate

Consider the following cases
Case 1:
If SMIs happen between (2) and (3) above, we can end up with a
loops_per_jiffy value that is too low. This results in shorted delays and
kernel can panic () during boot (Mostly at IOAPIC timer initialization
timer_irq_works() as we don't have enough timer interrupts in a specified
interval).

Case 2:
If SMIs happen between (3) and (4) above, then we can end up with a
loops_per_jiffy value that is too high. And with current i386 code, too
high lpj value (greater than 17M) can result in a overflow in
delay.c:__const_udelay() again resulting in shorter delay and panic().

Solution:
The patch below makes the calibration routine aware of asynchronous events
like SMIs. We increase the delay calibration time and also identify any
significant errors (greater than 12.5%) in the calibration and notify it to
user.

Patch below changes both i386 and x86-64 architectures to use this
new and improved calibrate_delay_direct() routine.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 09:45:08 -07:00
Dave Jones
c5d28fb297 [CPUFREQ] Recalibrate cpu_khz [2/2]
Some cpufreq drivers (at that time, only powernow-k7) need to recalibrate the
cpu_khz at runtime.

Signed-off-by: Bruno Ducrot <ducrot@poupinou.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>
2005-05-31 19:03:46 -07:00
john stultz
35492df5ae [PATCH] i386: fix hpet for systems that don't support legacy replacement
Currently the i386 HPET code assumes the entire HPET implementation from
the spec is present.  This breaks on boxes that do not implement the
optional legacy timer replacement functionality portion of the spec.

This patch, which is very similar to my x86-64 patch for the same issue,
fixes the problem allowing i386 systems that cannot use the HPET for the
timer interrupt and RTC to still use the HPET as a time source.  I've
tested this patch on a system systems without HPET, with HPET but without
legacy timer replacement, as well as HPET with legacy timer replacement.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 08:58:50 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
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!
2005-04-16 15:20:36 -07:00