lkml.org 
[lkml]   [2007]   [Apr]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH] [5/35] x86_64: always use physical delivery mode on > 8 CPUs
    Date

    From: Ingo Molnar <mingo@elte.hu>

    Remove clustered APIC mode. There's little point in the use of clustered APIC
    mode, broadcasting is limited to within the cluster only, and chipsets have
    bugs in this area as well. So default to physical APIC mode when the CPU
    count is large, and default to logical APIC mode when the CPU count is 8 or
    smaller.

    (this patch only removes the use of genapic_cluster and cleans up the
    resulting genapic.c file - removal of all remaining traces of clustered
    mode will be done by another patch.)

    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Andi Kleen <ak@suse.de>
    Cc: Suresh Siddha <suresh.b.siddha@intel.com>
    Cc: Andi Kleen <ak@suse.de>
    Cc: "Li, Shaohua" <shaohua.li@intel.com>
    Cc: "Eric W. Biederman" <ebiederm@xmission.com>
    Signed-off-by: Andrew Morton <akpm@osdl.org>
    ---

    arch/x86_64/kernel/genapic.c | 71 +++++++++----------------------------------
    include/asm-x86_64/genapic.h | 4 +-
    2 files changed, 18 insertions(+), 57 deletions(-)

    Index: linux/arch/x86_64/kernel/genapic.c
    ===================================================================
    --- linux.orig/arch/x86_64/kernel/genapic.c
    +++ linux/arch/x86_64/kernel/genapic.c
    @@ -11,26 +11,24 @@
    #include <linux/threads.h>
    #include <linux/cpumask.h>
    #include <linux/string.h>
    +#include <linux/module.h>
    #include <linux/kernel.h>
    #include <linux/ctype.h>
    #include <linux/init.h>
    -#include <linux/module.h>

    #include <asm/smp.h>
    #include <asm/ipi.h>

    -#if defined(CONFIG_ACPI)
    +#ifdef CONFIG_ACPI
    #include <acpi/acpi_bus.h>
    #endif

    /* which logical CPU number maps to which CPU (physical APIC ID) */
    -u8 x86_cpu_to_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID };
    +u8 x86_cpu_to_apicid[NR_CPUS] __read_mostly
    + = { [0 ... NR_CPUS-1] = BAD_APICID };
    EXPORT_SYMBOL(x86_cpu_to_apicid);
    -u8 x86_cpu_to_log_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };

    -extern struct genapic apic_cluster;
    -extern struct genapic apic_flat;
    -extern struct genapic apic_physflat;
    +u8 x86_cpu_to_log_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };

    struct genapic __read_mostly *genapic = &apic_flat;

    @@ -39,76 +37,37 @@ struct genapic __read_mostly *genapic =
    */
    void __init clustered_apic_check(void)
    {
    - int i;
    - u8 clusters, max_cluster;
    + unsigned int i, max_apic = 0;
    u8 id;
    - u8 cluster_cnt[NUM_APIC_CLUSTERS];
    - int max_apic = 0;

    #ifdef CONFIG_ACPI
    /*
    - * Some x86_64 machines use physical APIC mode regardless of how many
    - * procs/clusters are present (x86_64 ES7000 is an example).
    + * Quirk: some x86_64 machines can only use physical APIC mode
    + * regardless of how many processors are present (x86_64 ES7000
    + * is an example).
    */
    - if (acpi_gbl_FADT.header.revision > FADT2_REVISION_ID)
    - if (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL) {
    - genapic = &apic_cluster;
    - goto print;
    - }
    + if (acpi_gbl_FADT.header.revision > FADT2_REVISION_ID &&
    + (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL))
    + genapic = &apic_physflat;
    #endif

    - memset(cluster_cnt, 0, sizeof(cluster_cnt));
    for (i = 0; i < NR_CPUS; i++) {
    id = bios_cpu_apicid[i];
    if (id == BAD_APICID)
    continue;
    if (id > max_apic)
    max_apic = id;
    - cluster_cnt[APIC_CLUSTERID(id)]++;
    }

    - /*
    - * Don't use clustered mode on AMD platforms, default
    - * to flat logical mode.
    - */
    - if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
    - /*
    - * Switch to physical flat mode if more than 8 APICs
    - * (In the case of 8 CPUs APIC ID goes from 0 to 7):
    - */
    - if (max_apic >= 8)
    - genapic = &apic_physflat;
    - goto print;
    - }
    -
    - clusters = 0;
    - max_cluster = 0;
    -
    - for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
    - if (cluster_cnt[i] > 0) {
    - ++clusters;
    - if (cluster_cnt[i] > max_cluster)
    - max_cluster = cluster_cnt[i];
    - }
    - }
    -
    - /*
    - * If we have clusters <= 1 and CPUs <= 8 in cluster 0, then flat mode,
    - * else if max_cluster <= 4 and cluster_cnt[15] == 0, clustered logical
    - * else physical mode.
    - * (We don't use lowest priority delivery + HW APIC IRQ steering, so
    - * can ignore the clustered logical case and go straight to physical.)
    - */
    - if (clusters <= 1 && max_cluster <= 8 && cluster_cnt[0] == max_cluster)
    + if (max_apic < 8)
    genapic = &apic_flat;
    else
    - genapic = &apic_cluster;
    + genapic = &apic_physflat;

    -print:
    printk(KERN_INFO "Setting APIC routing to %s\n", genapic->name);
    }

    -/* Same for both flat and clustered. */
    +/* Same for both flat and physical. */

    void send_IPI_self(int vector)
    {
    Index: linux/include/asm-x86_64/genapic.h
    ===================================================================
    --- linux.orig/include/asm-x86_64/genapic.h
    +++ linux/include/asm-x86_64/genapic.h
    @@ -29,7 +29,9 @@ struct genapic {
    unsigned int (*phys_pkg_id)(int index_msb);
    };

    -
    extern struct genapic *genapic;

    +extern struct genapic apic_flat;
    +extern struct genapic apic_physflat;
    +
    #endif
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/
    \
     
     \ /
      Last update: 2007-04-28 20:23    [W:0.026 / U:30.064 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site