Re: [PATCH v15 10/12] hmat acpi: Build System Locality Latency and Bandwidth Information Structure(s)

[Igor Mammedov <imammedo@redhat.com>]

On Thu,  7 Nov 2019 15:45:09 +0800
Tao Xu <tao3.xu@intel.com> wrote:

> From: Liu Jingqi <jingqi.liu@intel.com>
> 
> This structure describes the memory access latency and bandwidth
> information from various memory access initiator proximity domains.
> The latency and bandwidth numbers represented in this structure
> correspond to rated latency and bandwidth for the platform.
> The software could use this information as hint for optimization.
> 
> Signed-off-by: Liu Jingqi <jingqi.liu@intel.com>
> Signed-off-by: Tao Xu <tao3.xu@intel.com>
> ---
> 
> No changes in v15.
> 
> Changes in v13:
>     - Calculate the entries in a new patch.
> ---
>  hw/acpi/hmat.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 95 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/acpi/hmat.c b/hw/acpi/hmat.c
> index c595098ba7..6ec1310e62 100644
> --- a/hw/acpi/hmat.c
> +++ b/hw/acpi/hmat.c
> @@ -27,6 +27,7 @@
>  #include "qemu/osdep.h"
>  #include "sysemu/numa.h"
>  #include "hw/acpi/hmat.h"
> +#include "qemu/error-report.h"
>  
>  /*
>   * ACPI 6.3:
> @@ -67,11 +68,81 @@ static void build_hmat_mpda(GArray *table_data, uint16_t flags,
>      build_append_int_noprefix(table_data, 0, 8);
>  }
>  
> +/*
> + * ACPI 6.3: 5.2.27.4 System Locality Latency and Bandwidth Information
> + * Structure: Table 5-146
> + */
> +static void build_hmat_lb(GArray *table_data, HMAT_LB_Info *hmat_lb,
> +                          uint32_t num_initiator, uint32_t num_target,
> +                          uint32_t *initiator_list)
> +{
> +    int i;
> +    uint16_t *lb_data;
> +    uint32_t base;
> +    /*
> +     * Length in bytes for entire structure, including 32 bytes of
> +     * fixed length, length of initiator proximity domain list,
> +     * length of target proximity domain list and length of entries
> +     * provides latency/bandwidth values.
> +     */
> +    uint32_t lb_length = 32 + 4 * num_initiator + 4 * num_target +
> +                              2 * num_initiator * num_target;
might be described better using field names from spec, as:

  uint32_t len = 32 /* table length upto and including Entry Base Unit */
                 + 4 * num_initiator /* Initiator Proximity Domain List */
                 + 4 * num_target /* Target Proximity Domain */
                 ....

> +
> +    /* Type */
> +    build_append_int_noprefix(table_data, 1, 2);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 2);
> +    /* Length */
> +    build_append_int_noprefix(table_data, lb_length, 4);
> +    /* Flags: Bits [3:0] Memory Hierarchy, Bits[7:4] Reserved */
> +    assert(!(hmat_lb->hierarchy >> 4));
> +    build_append_int_noprefix(table_data, hmat_lb->hierarchy, 1);
> +    /* Data Type */
> +    build_append_int_noprefix(table_data, hmat_lb->data_type, 1);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 2);
> +    /* Number of Initiator Proximity Domains (s) */
> +    build_append_int_noprefix(table_data, num_initiator, 4);
> +    /* Number of Target Proximity Domains (t) */
> +    build_append_int_noprefix(table_data, num_target, 4);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 4);
> +

> +    if (hmat_lb->data_type <= HMAT_LB_DATA_WRITE_LATENCY) {
> +        base = hmat_lb->base_latency;
> +        lb_data = hmat_lb->entry_latency;
> +    } else {
> +        base = hmat_lb->base_bandwidth;
> +        lb_data = hmat_lb->entry_bandwidth;
> +    }
I'd move this out into caller hmat_build_table_structs() and instead of
hmat_lb pass as arguments data_type, base and data, to keep subtable
API independent of internal NUMA structures.

On this note, considering that a single hmat_lb can represent either
latency or bandwidth only, I'd suggest to unify
   hmat_lb->base_latency/hmat_lb->base_bandwidth
     into hmat_lb->base
   
and do the same for data entries and use hmat_lb->data_type as discriminator.

That should simplify code here and in CLI parsing part as well,
I don't see any reason to keep them separate. 

> +
> +    /* Entry Base Unit */
> +    build_append_int_noprefix(table_data, base, 8);
> +
> +    /* Initiator Proximity Domain List */
> +    for (i = 0; i < num_initiator; i++) {
> +        build_append_int_noprefix(table_data, initiator_list[i], 4);
> +    }
> +
> +    /* Target Proximity Domain List */
> +    for (i = 0; i < num_target; i++) {
> +        build_append_int_noprefix(table_data, i, 4);
> +    }
> +
> +    /* Latency or Bandwidth Entries */
> +    for (i = 0; i < num_initiator * num_target; i++) {
> +        build_append_int_noprefix(table_data, lb_data[i], 2);
> +    }
> +}
> +
>  /* Build HMAT sub table structures */
>  static void hmat_build_table_structs(GArray *table_data, NumaState *numa_state)
>  {
>      uint16_t flags;
> -    int i;
> +    uint32_t num_initiator = 0;
> +    uint32_t initiator_list[MAX_NODES];
> +    int i, hierarchy, type;
> +    HMAT_LB_Info *hmat_lb;
>  
>      for (i = 0; i < numa_state->num_nodes; i++) {
>          flags = 0;
> @@ -82,6 +153,29 @@ static void hmat_build_table_structs(GArray *table_data, NumaState *numa_state)
>  
>          build_hmat_mpda(table_data, flags, numa_state->nodes[i].initiator, i);
>      }
> +
> +    for (i = 0; i < numa_state->num_nodes; i++) {
> +        if (numa_state->nodes[i].has_cpu) {
> +            initiator_list[num_initiator++] = i;
> +        }
> +    }
> +
> +    /*
> +     * ACPI 6.3: 5.2.27.4 System Locality Latency and Bandwidth Information
> +     * Structure: Table 5-146
> +     */
> +    for (hierarchy = HMAT_LB_MEM_MEMORY;
> +         hierarchy <= HMAT_LB_MEM_CACHE_3RD_LEVEL; hierarchy++) {
> +        for (type = HMAT_LB_DATA_ACCESS_LATENCY;
> +             type <= HMAT_LB_DATA_WRITE_BANDWIDTH; type++) {
> +            hmat_lb = numa_state->hmat_lb[hierarchy][type];
> +
> +            if (hmat_lb) {
> +                build_hmat_lb(table_data, hmat_lb, num_initiator,
> +                              numa_state->num_nodes, initiator_list);
> +            }
> +        }
> +    }
>  }
>  
>  void build_hmat(GArray *table_data, BIOSLinker *linker, NumaState *numa_state)