Alan,
Attached patch provides Alpha support for the O(1) scheduler in 2.4-ac.
This is based off the Alpha O(1) support in 2.4-aa by Andrea Arcangeli.
Patch is against 2.4.19-pre10-ac2, please apply.
Robert Love
--=-B9EKbwMuA45Wrwnb7gvh
Content-Disposition: attachment; filename=sched-O1-alpha-2.4.19-pre10-ac2-1.patch
Content-Transfer-Encoding: quoted-printable
Content-Type: text/x-patch; name=sched-O1-alpha-2.4.19-pre10-ac2-1.patch;
charset=ISO-8859-1
diff -urN linux-2.4.19-pre10-ac2/arch/alpha/kernel/process.c linux/arch/alp=
ha/kernel/process.c
--- linux-2.4.19-pre10-ac2/arch/alpha/kernel/process.c Thu Jun 6 08:55:05 =
2002
+++ linux/arch/alpha/kernel/process.c Thu Jun 13 12:16:23 2002
@@ -30,6 +30,7 @@
#include <linux/reboot.h>
#include <linux/tty.h>
#include <linux/console.h>
+#include <linux/sched_runqueue.h>
=20
#include <asm/reg.h>
#include <asm/uaccess.h>
@@ -74,9 +75,6 @@
cpu_idle(void)
{
/* An endless idle loop with no priority at all. */
- current->nice =3D 20;
- current->counter =3D -100;
-
while (1) {
/* FIXME -- EV6 and LCA45 know how to power down
the CPU. */
diff -urN linux-2.4.19-pre10-ac2/arch/alpha/kernel/smp.c linux/arch/alpha/k=
ernel/smp.c
--- linux-2.4.19-pre10-ac2/arch/alpha/kernel/smp.c Thu Jun 6 08:55:05 2002
+++ linux/arch/alpha/kernel/smp.c Thu Jun 13 12:16:23 2002
@@ -82,6 +82,7 @@
int smp_num_cpus =3D 1; /* Number that came online. */
int smp_threads_ready; /* True once the per process idle is forked. */
cycles_t cacheflush_time;
+unsigned long cache_decay_ticks;
=20
int __cpu_number_map[NR_CPUS];
int __cpu_logical_map[NR_CPUS];
@@ -156,11 +157,6 @@
{
int cpuid =3D hard_smp_processor_id();
=20
- if (current !=3D init_tasks[cpu_number_map(cpuid)]) {
- printk("BUG: smp_calling: cpu %d current %p init_tasks[cpu_number_map(cp=
uid)] %p\n",
- cpuid, current, init_tasks[cpu_number_map(cpuid)]);
- }
-
DBGS(("CALLIN %d state 0x%lx\n", cpuid, current->state));
=20
/* Turn on machine checks. */
@@ -215,9 +211,6 @@
DBGS(("smp_callin: commencing CPU %d current %p\n",
cpuid, current));
=20
- /* Setup the scheduler for this processor. */
- init_idle();
-
/* ??? This should be in init_idle. */
atomic_inc(&init_mm.mm_count);
current->active_mm =3D &init_mm;
@@ -236,8 +229,9 @@
smp_tune_scheduling (int cpuid)
{
struct percpu_struct *cpu;
- unsigned long on_chip_cache;
- unsigned long freq;
+ unsigned long on_chip_cache; /* kB */
+ unsigned long freq; /* Hz */
+ unsigned long bandwidth =3D 350; /* MB/s */
=20
cpu =3D (struct percpu_struct*)((char*)hwrpb + hwrpb->processor_offset
+ cpuid * hwrpb->processor_size);
@@ -258,29 +252,21 @@
=20
case EV6_CPU:
case EV67_CPU:
- on_chip_cache =3D 64 + 64;
- break;
-
default:
- on_chip_cache =3D 8 + 8;
+ on_chip_cache =3D 64 + 64;
break;
}
=20
freq =3D hwrpb->cycle_freq ? : est_cycle_freq;
=20
-#if 0
- /* Magic estimation stolen from x86 port. */
- cacheflush_time =3D freq / 1024L * on_chip_cache / 5000L;
-
- printk("Using heuristic of %d cycles.\n",
- cacheflush_time);
-#else
- /* Magic value to force potential preemption of other CPUs. */
- cacheflush_time =3D INT_MAX;
+ cacheflush_time =3D (freq / 1000000) * (on_chip_cache << 10) / bandwidth;
+ cache_decay_ticks =3D cacheflush_time / (freq / 1000) * HZ / 1000;
=20
- printk("Using heuristic of %d cycles.\n",
- cacheflush_time);
-#endif
+ printk("per-CPU timeslice cutoff: %ld.%02ld usecs.\n",
+ cacheflush_time/(freq/1000000),
+ (cacheflush_time*100/(freq/1000000)) % 100);
+ printk("task migration cache decay timeout: %ld msecs.\n",
+ (cache_decay_ticks + 1) * 1000 / HZ);
}
=20
/*
@@ -505,14 +491,11 @@
if (idle =3D=3D &init_task)
panic("idle process is init_task for CPU %d", cpuid);
=20
- idle->processor =3D cpuid;
- idle->cpus_runnable =3D 1 << cpuid; /* we schedule the first task manuall=
y */
+ init_idle(idle, cpuid);
+ unhash_process(idle);
+
__cpu_logical_map[cpunum] =3D cpuid;
__cpu_number_map[cpuid] =3D cpunum;
-=20
- del_from_runqueue(idle);
- unhash_process(idle);
- init_tasks[cpunum] =3D idle;
=20
DBGS(("smp_boot_one_cpu: CPU %d state 0x%lx flags 0x%lx\n",
cpuid, idle->state, idle->flags));
@@ -619,14 +602,11 @@
=20
__cpu_number_map[boot_cpuid] =3D 0;
__cpu_logical_map[0] =3D boot_cpuid;
- current->processor =3D boot_cpuid;
=20
smp_store_cpu_info(boot_cpuid);
smp_tune_scheduling(boot_cpuid);
smp_setup_percpu_timer(boot_cpuid);
=20
- init_idle();
-
/* ??? This should be in init_idle. */
atomic_inc(&init_mm.mm_count);
current->active_mm =3D &init_mm;
diff -urN linux-2.4.19-pre10-ac2/include/asm-alpha/bitops.h linux/include/a=
sm-alpha/bitops.h
--- linux-2.4.19-pre10-ac2/include/asm-alpha/bitops.h Thu Jun 6 08:54:10 2=
002
+++ linux/include/asm-alpha/bitops.h Thu Jun 13 12:16:23 2002
@@ -3,6 +3,7 @@
=20
#include <linux/config.h>
#include <linux/kernel.h>
+#include <asm/compiler.h>
=20
/*
* Copyright 1994, Linus Torvalds.
@@ -74,6 +75,17 @@
* WARNING: non atomic version.
*/
static __inline__ void
+__clear_bit(unsigned long nr, volatile void * addr)
+{
+ int *m =3D ((int *) addr) + (nr >> 5);
+
+ *m &=3D ~(1 << (nr & 31));
+}
+
+/*
+ * WARNING: non atomic version.
+ */
+static __inline__ void
__change_bit(unsigned long nr, volatile void * addr)
{
int *m =3D ((int *) addr) + (nr >> 5);
@@ -264,6 +276,28 @@
#endif
}
=20
+/*
+ * __ffs =3D Find First set bit in word. Undefined if no set bit exists.
+ */
+static inline unsigned long __ffs(unsigned long word)
+{
+#if defined(__alpha_cix__) && defined(__alpha_fix__)
+ /* Whee. EV67 can calculate it directly. */
+ unsigned long result;
+ __asm__("cttz %1,%0" : "=3Dr"(result) : "r"(word));
+ return result;
+#else
+ unsigned long bits, qofs, bofs;
+
+ __asm__("cmpbge $31,%1,%0" : "=3Dr"(bits) : "r"(word));
+ qofs =3D ffz_b(bits);
+ bits =3D __kernel_extbl(word, qofs);
+ bofs =3D ffz_b(~bits);
+
+ return qofs*8 + bofs;
+#endif
+}
+
#ifdef __KERNEL__
=20
/*
@@ -365,13 +399,77 @@
}
=20
/*
- * The optimizer actually does good code for this case..
+ * Find next one bit in a bitmap reasonably efficiently.
+ */
+static inline unsigned long
+find_next_bit(void * addr, unsigned long size, unsigned long offset)
+{
+ unsigned long * p =3D ((unsigned long *) addr) + (offset >> 6);
+ unsigned long result =3D offset & ~63UL;
+ unsigned long tmp;
+
+ if (offset >=3D size)
+ return size;
+ size -=3D result;
+ offset &=3D 63UL;
+ if (offset) {
+ tmp =3D *(p++);
+ tmp &=3D ~0UL << offset;
+ if (size < 64)
+ goto found_first;
+ if (tmp)
+ goto found_middle;
+ size -=3D 64;
+ result +=3D 64;
+ }
+ while (size & ~63UL) {
+ if ((tmp =3D *(p++)))
+ goto found_middle;
+ result +=3D 64;
+ size -=3D 64;
+ }
+ if (!size)
+ return result;
+ tmp =3D *p;
+found_first:
+ tmp &=3D ~0UL >> (64 - size);
+ if (!tmp)
+ return result + size;
+found_middle:
+ return result + __ffs(tmp);
+}
+
+/*
+ * The optimizer actually does good code for this case.
*/
#define find_first_zero_bit(addr, size) \
find_next_zero_bit((addr), (size), 0)
+#define find_first_bit(addr, size) \
+ find_next_bit((addr), (size), 0)
=20
#ifdef __KERNEL__
=20
+/*
+ * Every architecture must define this function. It's the fastest
+ * way of searching a 140-bit bitmap where the first 100 bits are
+ * unlikely to be set. It's guaranteed that at least one of the 140
+ * bits is set.
+ */
+static inline unsigned long
+sched_find_first_bit(unsigned long b[3])
+{
+ unsigned long b0 =3D b[0], b1 =3D b[1], b2 =3D b[2];
+ unsigned long ofs;
+
+ ofs =3D (b1 ? 64 : 128);
+ b1 =3D (b1 ? b1 : b2);
+ ofs =3D (b0 ? 0 : ofs);
+ b0 =3D (b0 ? b0 : b1);
+
+ return __ffs(b0) + ofs;
+}
+
+
#define ext2_set_bit __test_and_set_bit
#define ext2_clear_bit __test_and_clear_bit
#define ext2_test_bit test_bit
diff -urN linux-2.4.19-pre10-ac2/include/asm-alpha/smp.h linux/include/asm-=
alpha/smp.h
--- linux-2.4.19-pre10-ac2/include/asm-alpha/smp.h Thu Jun 6 08:54:10 2002
+++ linux/include/asm-alpha/smp.h Thu Jun 13 12:16:23 2002
@@ -55,7 +55,7 @@
#define cpu_logical_map(cpu) __cpu_logical_map[cpu]
=20
#define hard_smp_processor_id() __hard_smp_processor_id()
-#define smp_processor_id() (current->processor)
+#define smp_processor_id() (current->cpu)
=20
extern unsigned long cpu_present_mask;
#define cpu_online_map cpu_present_mask
--=-B9EKbwMuA45Wrwnb7gvh--
-
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