[3/3] ARTiS, an asymmetric real-time scheduler - IA-64

Eric Piel
2005-05-03T14:14:32Z

[-- Attachment #1: Type: text/plain, Size: 72 bytes --]

Here is the Here is the architecture dependant part of ARTiS for IA-64.

[-- Attachment #2: artis-2.6.11-20050502-ia64.patch --]
[-- Type: text/x-patch, Size: 6294 bytes --]

diff -urpN -X /export/src/patches/dontdiff -X /export/src/patches/dontdiff2 2.6.11-pfm/arch/ia64/Kconfig 2.6.11-artis-cvs/arch/ia64/Kconfig
--- 2.6.11-pfm/arch/ia64/Kconfig 2005-03-02 08:38:26.000000000 +0100
+++ 2.6.11-artis-cvs/arch/ia64/Kconfig 2005-04-22 18:08:19.000000000 +0200
@@ -46,6 +46,32 @@ config GENERIC_IOMAP
bool
default y

+config ARTIS
+ bool "Compile the kernel with ARTiS support (EXPERIMENTAL)"
+ depends on PREEMPT && SMP
+ help
+ ARTiS is an "Asymmetric Real-Time Scheduling". When activated,
+ the real-time tasks will be insured of low latencies. It works
+ by automatically migrating the normal tasks out from CPUs running
+ real-time tasks when they would trigger a preemption disable or an
+ IRQ disable. Obviously, a SMP system is required (SMT works too).
+ Note that it will not be activated by default, you need to select
+ it at boot time. For more information, see Documentation/artis.txt.
+
+config ARTIS_DEBUG
+ bool "Compile the kernel with ARTiS debugging support (EXPERIMENTAL)"
+ depends on ARTIS
+ help
+ Activate debuging code in ARTiS, you probably don't want this, excepted
+ if you want to hack on ARTiS.
+
+config ARTIS_STAT
+ bool "Compile the kernel with ARTiS accounting support (EXPERIMENTAL)"
+ depends on ARTIS
+ help
+ Activate statistics about ARTiS, available in /proc. There is no (or
+ very little) performance penalty, so you can safely say "yes" here.
+
choice
prompt "System type"
default IA64_GENERIC
diff -urpN -X /export/src/patches/dontdiff -X /export/src/patches/dontdiff2 2.6.11-pfm/arch/ia64/kernel/process.c 2.6.11-artis-cvs/arch/ia64/kernel/process.c
--- 2.6.11-pfm/arch/ia64/kernel/process.c 2005-03-02 08:38:08.000000000 +0100
+++ 2.6.11-artis-cvs/arch/ia64/kernel/process.c 2005-03-25 19:47:46.000000000 +0100
@@ -229,6 +229,43 @@ static inline void play_dead(void)
}
#endif /* CONFIG_HOTPLUG_CPU */

+#ifdef CONFIG_ARTIS_DEBUG
+#include <linux/artis.h>
+void
+artis_ia64_put_trace(struct unw_frame_info *info, void *arg)
+{
+ void **bt = (void **)arg;
+ int i, artis_skip_bt, r_unw;
+ unsigned long ip, sp, bsp;
+
+ memset(bt, 0, ARTIS_BT_SIZE*sizeof(void *));
+ r_unw=0;
+ artis_skip_bt=0;
+ for(i=artis_skip_bt-1;
+ i>=0 && r_unw>=0;
+ i--, r_unw=unw_unwind(info)) {
+ unw_get_ip(info, &ip);
+ if (ip == 0)
+ break;
+ unw_get_sp(info, &sp);
+ unw_get_bsp(info, &bsp);
+ }
+ for(i=ARTIS_BT_SIZE-1;
+ i>=0 && r_unw>=0;
+ i--, r_unw=unw_unwind(info)) {
+ unw_get_ip(info, &ip);
+ if (ip == 0)
+ break;
+ unw_get_sp(info, &sp);
+ unw_get_bsp(info, &bsp);
+ bt[i] = (void *)ip;
+ }
+}
+void
+artis_put_trace(void **bt, struct task_struct *task, unsigned long *stack) {
+ unw_init_running(artis_ia64_put_trace, (void *)bt);
+}
+#endif

void cpu_idle_wait(void)
{
diff -urpN -X /export/src/patches/dontdiff -X /export/src/patches/dontdiff2 2.6.11-pfm/include/asm-ia64/bug.h 2.6.11-artis-cvs/include/asm-ia64/bug.h
--- 2.6.11-pfm/include/asm-ia64/bug.h 2005-03-02 08:38:34.000000000 +0100
+++ 2.6.11-artis-cvs/include/asm-ia64/bug.h 2005-03-25 19:47:46.000000000 +0100
@@ -1,12 +1,20 @@
#ifndef _ASM_IA64_BUG_H
#define _ASM_IA64_BUG_H

+#include <linux/artis-macros.h>
+
#if (__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1)
# define ia64_abort() __builtin_trap()
#else
# define ia64_abort() (*(volatile int *) 0 = 0)
#endif
-#define BUG() do { printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); ia64_abort(); } while (0)
+#define _old_BUG() do { printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); ia64_abort(); } while (0)
+
+#if defined(CONFIG_ARTIS_DEBUG)
+#define BUG() do { ARTIS_BUG(1,0); } while (0)
+#else
+#define BUG() _old_BUG()
+#endif

/* should this BUG should be made generic? */
#define HAVE_ARCH_BUG
diff -urpN -X /export/src/patches/dontdiff -X /export/src/patches/dontdiff2 2.6.11-pfm/include/asm-ia64/system.h 2.6.11-artis-cvs/include/asm-ia64/system.h
--- 2.6.11-pfm/include/asm-ia64/system.h 2005-03-02 08:38:07.000000000 +0100
+++ 2.6.11-artis-cvs/include/asm-ia64/system.h 2005-03-25 19:47:46.000000000 +0100
@@ -121,7 +121,7 @@ extern struct ia64_boot_param {
* write a floating-point register right before reading the PSR
* and that writes to PSR.mfl
*/
-#define __local_irq_save(x) \
+#define _raw__local_irq_save(x) \
do { \
ia64_stop(); \
(x) = ia64_getreg(_IA64_REG_PSR); \
@@ -129,13 +129,47 @@ do { \
ia64_rsm(IA64_PSR_I); \
} while (0)

-#define __local_irq_disable() \
+#define _raw__local_irq_disable() \
do { \
ia64_stop(); \
ia64_rsm(IA64_PSR_I); \
} while (0)

-#define __local_irq_restore(x) ia64_intrin_local_irq_restore((x) & IA64_PSR_I)
+#define _raw__local_irq_restore(x) ia64_intrin_local_irq_restore((x) & IA64_PSR_I)
+
+#ifdef CONFIG_ARTIS
+#include <linux/artis-macros.h>
+
+/* Overwrite all functions "dangerous" for real-time: migrate task on
+ * non real-time CPU */
+
+#define __local_irq_save(x) \
+do { \
+ artis_force_migration(); \
+ _raw__local_irq_save(x); \
+} while (0)
+
+#define __local_irq_disable() \
+do { \
+ artis_force_migration(); \
+ _raw__local_irq_disable(); \
+} while (0)
+
+#define __local_irq_restore(x) \
+do { \
+ if (!((x) & IA64_PSR_I)) \
+ artis_force_migration(); \
+ _raw__local_irq_restore(x); \
+} while (0)
+
+#else
+
+#define __local_irq_save(x) _raw__local_irq_save(x)
+#define __local_irq_disable() _raw__local_irq_disable()
+#define __local_irq_restore(x) _raw__local_irq_restore(x)
+
+#endif
+

#ifdef CONFIG_IA64_DEBUG_IRQ

@@ -282,6 +316,20 @@ do { \
#define finish_arch_switch(rq, prev) spin_unlock_irq(&(prev)->switch_lock)
#define task_running(rq, p) ((rq)->curr == (p) || spin_is_locked(&(p)->switch_lock))

+#ifdef CONFIG_ARTIS
+/* On IA64, the end of scheduler releases the runqueue lock,
+ * so a wake-up has re-activated the task and we must
+ * deactivate it
+ * */
+#define artis_complete_arch(rq, task) \
+do { \
+ spin_lock(&(rq)->lock); \
+ if ((task)->array) \
+ deactivate_task((task),(rq)); \
+} while(0)
+#define artis_finish_complete_arch(rq, task) spin_unlock(&(rq)->lock)
+#endif
+
#define ia64_platform_is(x) (strcmp(x, platform_name) == 0)

void cpu_idle_wait(void);