On Wed, 9 Oct 2019 14:39:46 +0800
Tao Xu <address@hidden> wrote:
On 10/2/2019 11:16 PM, Igor Mammedov wrote:
On Fri, 20 Sep 2019 15:43:44 +0800
Tao Xu <address@hidden> wrote:
[...]
+struct HMAT_LB_Info {
+ /* Indicates it's memory or the specified level memory side cache. */
+ uint8_t hierarchy;
+
+ /* Present the type of data, access/read/write latency or bandwidth. */
+ uint8_t data_type;
+
+ /* Array to store the latencies */
specify units it's stored in
+ uint64_t *latency;
+
+ /* Array to store the bandwidthes */
ditto
+ uint64_t *bandwidth;
btw:
what was the reason for picking uint64_t for storing above values?
it seems in this patch you dumb down bandwidth to MB/s above but
store latency as is.
Because I want to store the bandwidth or latency value (minimum unit)
that user input. In HMAT, the minimum unit of bandwidth is MB/s, but in
QAPI, the minimum unit of size is Byte. So I convert size into MB/s and
time unit is "ps", need not convert.
Just be consistent and store (user input) raw values for both fields
(i.e. B/s PS/s) and post-process them later to uint16_t.
and then in 9/11 build_hmat_lb you divide that on 'base' units,
where are guaranties that value stored here will fit into 2 bytes
used in HMAT to store it in the table?
For HMAT spec, for a matrix of bandwidth or latency, there is only one
base (in order to save ACPI tables space). We need to extract base for a
matrix, but user input bandwidth or latency line by line. So after all
data input, we can extract the base (as in 9/11).
There is another benefit. If user input different but similar units,
such as "10ns" and "100ps", we can also store them. Only If user input
big gap units, such as "1ps" and "1000ms". we can't store them and raise
error.
No disagreement here,
but I suggest to move verification and base calculation from 09/11
into a separate patch (right after this one) and doing it at
numa_complete_configuration() time.
To store calculated base you can add a common_base field to
sub-table structure (HMAT_LB_Info) and use it when building ACPI
table without extra calculations.