[ath9k-devel] query in ath9k

[Luis R. Rodriguez <lrodriguez@atheros.com>]

On Mon, Mar 29, 2010 at 03:58:37AM -0700, selvam wrote:
> Hi all,
> I have some queries in ath9k.
> 
> In xmit.c, the variable 'bits_per_symbol' is used to store the number of bits per OFDM symbol for various data rates.
> 
> static u32 bits_per_symbol[][2] = {
>         /* 20MHz 40MHz */
>         {    26,   54 },     /*  0: BPSK */
>         {    52,  108 },     /*  1: QPSK 1/2 */
>         {    78,  162 },     /*  2: QPSK 3/4 */
>         {   104,  216 },     /*  3: 16-QAM 1/2 */
>         {   156,  324 },     /*  4: 16-QAM 3/4 */
>         {   208,  432 },     /*  5: 64-QAM 2/3 */
>         {   234,  486 },     /*  6: 64-QAM 3/4 */
>         {   260,  540 },     /*  7: 64-QAM 5/6 */
>         {    52,  108 },     /*  8: BPSK */
>         {   104,  216 },     /*  9: QPSK 1/2 */
>         {   156,  324 },     /* 10: QPSK 3/4 */
>         {   208,  432 },     /* 11: 16-QAM 1/2 */
>         {   312,  648 },     /* 12: 16-QAM 3/4 */
>         {   416,  864 },     /* 13: 64-QAM 2/3 */
>         {   468,  972 },     /* 14: 64-QAM 3/4 */
>         {   520, 1080 },     /* 15: 64-QAM 5/6 */
> 
> 
> 1) Is it possible to keep only the values of MCS 0 to MCS 7 and calculate the rest on run time. so that we can save some amount of memory.
> 
> For example, if MCS index is 8, then multiply the MCS 0 by 2, for MCS 9 mutiply MCS 1 by 2..
> 
> Can we use in that way?. Is there any performance tradeoff in terms of faster execution due to comparison?
> 
> 
> 2) Why don't we use static u16 instead of static u32 to declare this variable? Is there any specific reason for using as u32?
> 
> If my approach is improper, please excuse me.

Try the patch and send it once tested and proved to work :)

  Luis