Magellan Linux

  • Back to homepage
    • /[pkg-src]/trunk/kernel26-magellan/patches-2.6.16-r3/0002-2.6.16-sched-smpnice-apply-review-suggestions.patch

    Contents of /trunk/kernel26-magellan/patches-2.6.16-r3/0002-2.6.16-sched-smpnice-apply-review-suggestions.patch

    Parent Directory Parent Directory | Revision Log Revision Log

    Revision 70 - (show annotations) (download)
    Thu May 11 19:09:22 2006 UTC (18 years ago) by niro
    File size: 4150 byte(s) 
    import
    1
    2 From: Peter Williams <pwil3058@bigpond.net.au>
    3
    4 This patch applies the suggestions made by Con Kolivas for improving the
    5 smpnice code.
    6
    7 The non cosmetic part of the patch addresses the fact the mapping from nice
    8 values to task load weights for negative nice values does not match the
    9 implied CPU allocations in the function task_timeslice(). As suggested by
    10 Con the mapping function now uses the time slice information directly (via
    11 a slightly modified interface).
    12
    13 Signed-off-by: Peter Williams <pwil3058@bigpond.com.au>
    14 Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
    15 Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
    16 Cc: Ingo Molnar <mingo@elte.hu>
    17 Cc: Nick Piggin <nickpiggin@yahoo.com.au>
    18 Cc: Con Kolivas <kernel@kolivas.org>
    19 Cc: John Hawkes <hawkes@sgi.com>
    20 Signed-off-by: Andrew Morton <akpm@osdl.org>
    21 include/linux/sched.h | 6 +++---
    22 kernel/sched.c | 34 +++++++++++++++++++++-------------
    23 2 files changed, 24 insertions(+), 16 deletions(-)
    24
    25 Index: linux-2.6.16-ck1/include/linux/sched.h
    26 ===================================================================
    27 --- linux-2.6.16-ck1.orig/include/linux/sched.h 2006-03-20 20:46:44.000000000 +1100
    28 +++ linux-2.6.16-ck1/include/linux/sched.h 2006-03-20 20:46:44.000000000 +1100
    29 @@ -698,13 +698,13 @@ struct task_struct {
    30
    31 int lock_depth; /* BKL lock depth */
    32
    33 -#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
    34 +#ifdef CONFIG_SMP
    35 +#ifdef __ARCH_WANT_UNLOCKED_CTXSW
    36 int oncpu;
    37 #endif
    38 - int prio, static_prio;
    39 -#ifdef CONFIG_SMP
    40 int load_weight; /* for load balancing purposes */
    41 #endif
    42 + int prio, static_prio;
    43 struct list_head run_list;
    44 prio_array_t *array;
    45
    46 Index: linux-2.6.16-ck1/kernel/sched.c
    47 ===================================================================
    48 --- linux-2.6.16-ck1.orig/kernel/sched.c 2006-03-20 20:46:44.000000000 +1100
    49 +++ linux-2.6.16-ck1/kernel/sched.c 2006-03-20 20:46:44.000000000 +1100
    50 @@ -168,13 +168,19 @@
    51 #define SCALE_PRIO(x, prio) \
    52 max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO/2), MIN_TIMESLICE)
    53
    54 -static unsigned int task_timeslice(task_t *p)
    55 +static unsigned int static_prio_timeslice(int static_prio)
    56 {
    57 - if (p->static_prio < NICE_TO_PRIO(0))
    58 - return SCALE_PRIO(DEF_TIMESLICE*4, p->static_prio);
    59 + if (static_prio < NICE_TO_PRIO(0))
    60 + return SCALE_PRIO(DEF_TIMESLICE*4, static_prio);
    61 else
    62 - return SCALE_PRIO(DEF_TIMESLICE, p->static_prio);
    63 + return SCALE_PRIO(DEF_TIMESLICE, static_prio);
    64 }
    65 +
    66 +static inline unsigned int task_timeslice(task_t *p)
    67 +{
    68 + return static_prio_timeslice(p->static_prio);
    69 +}
    70 +
    71 #define task_hot(p, now, sd) ((long long) ((now) - (p)->last_ran) \
    72 < (long long) (sd)->cache_hot_time)
    73
    74 @@ -667,21 +673,23 @@ static int effective_prio(task_t *p)
    75 * To aid in avoiding the subversion of "niceness" due to uneven distribution
    76 * of tasks with abnormal "nice" values across CPUs the contribution that
    77 * each task makes to its run queue's load is weighted according to its
    78 - * scheduling class and "nice" value.
    79 + * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
    80 + * scaled version of the new time slice allocation that they receive on time
    81 + * slice expiry etc.
    82 */
    83
    84 /*
    85 - * Priority weight for load balancing ranges from 1/20 (nice==19) to 459/20 (RT
    86 - * priority of 100).
    87 + * Assume: static_prio_timeslice(NICE_TO_PRIO(0)) == DEF_TIMESLICE
    88 + * If static_prio_timeslice() is ever changed to break this assumption then
    89 + * this code will need modification
    90 */
    91 -#define NICE_TO_LOAD_PRIO(nice) \
    92 - ((nice >= 0) ? (20 - (nice)) : (20 + (nice) * (nice)))
    93 +#define TIME_SLICE_NICE_ZERO DEF_TIMESLICE
    94 #define LOAD_WEIGHT(lp) \
    95 - (((lp) * SCHED_LOAD_SCALE) / NICE_TO_LOAD_PRIO(0))
    96 -#define NICE_TO_LOAD_WEIGHT(nice) LOAD_WEIGHT(NICE_TO_LOAD_PRIO(nice))
    97 -#define PRIO_TO_LOAD_WEIGHT(prio) NICE_TO_LOAD_WEIGHT(PRIO_TO_NICE(prio))
    98 + (((lp) * SCHED_LOAD_SCALE) / TIME_SLICE_NICE_ZERO)
    99 +#define PRIO_TO_LOAD_WEIGHT(prio) \
    100 + LOAD_WEIGHT(static_prio_timeslice(prio))
    101 #define RTPRIO_TO_LOAD_WEIGHT(rp) \
    102 - LOAD_WEIGHT(NICE_TO_LOAD_PRIO(-20) + (rp))
    103 + (PRIO_TO_LOAD_WEIGHT(MAX_RT_PRIO) + LOAD_WEIGHT(rp))
    104
    105 static inline void set_load_weight(task_t *p)
    106 {