Re: [Qemu-devel] [PATCH v7 2/6] target/mips: Optimize ILVEV.<B|H|W|D> MSA instructions

[Richard Henderson]

On 4/17/19 5:33 AM, Mateja Marjanovic wrote:
> From: Mateja Marjanovic <address@hidden>
> 
> Optimize set of MSA instructions ILVEV.<B|H|W|D>, using
> directly tcg registers and performing logic on them
> instead of using helpers.
> 
> In the following table, the first column is the performance
> before this patch. The second represents the performance
> after converting from helpers to tcg, but without using
> tcg_gen_deposit function. The third one is with using the
> tcg_gen_deposit function and with using a uint64_t constant
> bit mask, and the fourth is with using the tcg_gen_deposit
> function and with a mask which is a tcg constant. The fourth
> is implemented in this patch.
> 
> Performance measurement is done by executing the
> instructions 10 million times on a computer
> with Intel Core i7-3770 CPU @ 3.40GHz×8.
> 
> ==================================================================
> || instruction ||     1     ||     2    ||     3    ||     4    ||
> ==================================================================
> ||   ilvev.b   || 126.92 ms || 24.52 ms || 25.19 ms || 23.89 ms ||
> ||   ilvev.h   ||  93.67 ms || 23.92 ms || 24.76 ms || 24.31 ms ||
> ||   ilvev.w   || 117.86 ms || 23.83 ms || 21.84 ms || 21.99 ms ||
> ||   ilvev.d   ||  45.49 ms || 19.74 ms || 20.21 ms || 20.07 ms ||
> ==================================================================
> 1 - before
> 2 - no-deposit-no-mask-as-tcg-constant
> 3 - with-deposit-no-mask-as-tcg-constant
> 4 - with-deposit-with-mask-as-tcg-constant (final)
> 
> The deposit function is used only in ILVEV.W.
> 
> No-deposit version of the ILVEV.W implementation:
> 
> static inline void gen_ilvev_w(CPUMIPSState *env, uint32_t wd,
>                                uint32_t ws, uint32_t wt)
> {
>     TCGv_i64 t1 = tcg_temp_new_i64();
>     TCGv_i64 t2 = tcg_temp_new_i64();
>     uint64_t mask = 0x00000000ffffffffULL;
> 
>     tcg_gen_andi_i64(t1, msa_wr_d[wt * 2], mask);
>     tcg_gen_andi_i64(t2, msa_wr_d[ws * 2], mask);
>     tcg_gen_shli_i64(t2, t2, 32);
>     tcg_gen_or_i64(msa_wr_d[wd * 2], t1, t2);
> 
>     tcg_gen_andi_i64(t1, msa_wr_d[wt * 2 + 1], mask);
>     tcg_gen_andi_i64(t2, msa_wr_d[ws * 2 + 1], mask);
>     tcg_gen_shli_i64(t2, t2, 32);
>     tcg_gen_or_i64(msa_wr_d[wd * 2 + 1], t1, t2);
> 
>     tcg_temp_free_i64(t1);
>     tcg_temp_free_i64(t2);
> }
> 
> Suggested-by: Aleksandar Markovic <address@hidden>
> Suggested-by: Philippe Mathieu-Daudé <address@hidden>
> Suggested-by: Richard Henderson <address@hidden>
> Signed-off-by: Mateja Marjanovic <address@hidden>
> ---
>  target/mips/helper.h     |  1 -
>  target/mips/msa_helper.c |  9 -----
>  target/mips/translate.c  | 87 
> +++++++++++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 86 insertions(+), 11 deletions(-)

Reviewed-by: Richard Henderson <address@hidden>


r~