linux-toradex.git/arch/s390/kernel/s390_ext.c, branch v2.6.35.7

[S390] idle time accounting vs. machine checks

2010-05-17T08:00:15+00:00

A machine check can interrupt the i/o and external interrupt handler
anytime. If the machine check occurs while the interrupt handler is
waking up from idle vtime_start_cpu can get executed a second time
and the int_clock / async_enter_timer values in the lowcore get
clobbered. This can confuse the cpu time accounting.
To fix this problem two changes are needed. First the machine check
handler has to use its own copies of int_clock and async_enter_timer,
named mcck_clock and mcck_enter_timer. Second the nested execution
of vtime_start_cpu has to be prevented. This is done in s390_idle_check
by checking the wait bit in the program status word.

Signed-off-by: Martin Schwidefsky

nohz: Introduce arch_needs_cpu

2009-11-05T06:53:53+00:00

Allow the architecture to request a normal jiffy tick when the system
goes idle and tick_nohz_stop_sched_tick is called . On s390 the hook is
used to prevent the system going fully idle if there has been an
interrupt other than a clock comparator interrupt since the last wakeup.

On s390 the HiperSockets response time for 1 connection ping-pong goes
down from 42 to 34 microseconds. The CPU cost decreases by 27%.

Signed-off-by: Martin Schwidefsky 
LKML-Reference: <20090929122533.402715150@de.ibm.com>
Signed-off-by: Thomas Gleixner

[S390] ftrace: add function graph tracer support

2009-06-12T08:27:39+00:00

Function graph tracer support for s390.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

[S390] merge cpu.h into cputime.h

2009-06-12T08:27:29+00:00

All definition in cpu.h have to do with cputime accounting. Move
them to cputime.h and remove the header file.

Signed-off-by: Martin Schwidefsky

[PATCH] improve idle cputime accounting

2008-12-31T14:11:48+00:00

Distinguish the cputime of the idle process where idle is actually using
cpu cycles from the cputime where idle is sleeping on an enabled wait psw.
The former is accounted as system time, the later as idle time.

Signed-off-by: Martin Schwidefsky

[S390] Fix a lot of sparse warnings.

2008-04-17T05:47:06+00:00

Most noteable part of this commit is the new local header file entry.h
which contains all the function declarations of functions that get only
called from asm code or are arch internal. That way we can avoid extern
declarations in C files.
This is more or less the same that was done for sparc64.

Signed-off-by: Martin Schwidefsky 
Signed-off-by: Heiko Carstens

[S390] Convert s390 to GENERIC_CLOCKEVENTS.

2008-04-17T05:47:05+00:00

This way we get rid of s390's NO_IDLE_HZ and use the generic dynticks
variant instead. In addition we get high resolution timers for free.

Signed-off-by: Martin Schwidefsky 
Signed-off-by: Heiko Carstens

[S390] Convert monitor calls to function calls.

2008-04-17T05:47:05+00:00

Remove the program check generating monitor calls and use function
calls instead. Theres is no real advantage in using monitor calls,
but they do make debugging harder, because of all the program checks
it generates.

Signed-off-by: Martin Schwidefsky 
Signed-off-by: Heiko Carstens

[S390] ETR support.

2007-02-05T20:18:19+00:00

This patch adds support for clock synchronization to an external time
reference (ETR). The external time reference sends an oscillator
signal and a synchronization signal every 2^20 microseconds to keep
the TOD clocks of all connected servers in sync. For availability
two ETR units can be connected to a machine. If the clock deviates
for more than the sync-check tolerance all cpus get a machine check
that indicates that the clock is out of sync. For the lovely details
how to get the clock back in sync see the code below.

Signed-off-by: Martin Schwidefsky

[PATCH] getting rid of all casts of k[cmz]alloc() calls

2006-12-13T17:05:58+00:00

Run this:

	#!/bin/sh
	for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do
	  echo "De-casting $f..."
	  perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f
	done

And then go through and reinstate those cases where code is casting pointers
to non-pointers.

And then drop a few hunks which conflicted with outstanding work.

Cc: Russell King , Ian Molton 
Cc: Mikael Starvik 
Cc: Yoshinori Sato 
Cc: Roman Zippel 
Cc: Geert Uytterhoeven 
Cc: Ralf Baechle 
Cc: Paul Mackerras 
Cc: Kyle McMartin 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: "David S. Miller" 
Cc: Jeff Dike 
Cc: Greg KH 
Cc: Jens Axboe 
Cc: Paul Fulghum 
Cc: Alan Cox 
Cc: Karsten Keil 
Cc: Mauro Carvalho Chehab 
Cc: Jeff Garzik 
Cc: James Bottomley 
Cc: Ian Kent 
Cc: Steven French 
Cc: David Woodhouse 
Cc: Neil Brown 
Cc: Jaroslav Kysela 
Cc: Takashi Iwai 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds