Re: [Qemu-devel] [PATCH v6 4/4] target/mips: Optimize ILVR.<B|H|W|D> MSA instructions

[Aleksandar Markovic <aleksandar.m.mail@gmail.com>]

On Thu, Apr 4, 2019 at 3:16 PM Mateja Marjanovic
<mateja.marjanovic@rt-rk.com> wrote:
>
> From: Mateja Marjanovic <Mateja.Marjanovic@rt-rk.com>
>
> Optimized ILVR.<B|H|W|D> instructions, using a hybrid

Optimized -> Optimize

> approach. For byte data elements, use a helper with an
> unrolled loop (much better performance), for halfword,

(much better performance) -> (having much better performance
than direct tcg translation)

> word and doubleword data elements use directly tcg
> registers and logic performed on them.
>
> Performance measurement is done by executing the
> instructions a large number of times on a computer
> with Intel Core i7-3770 CPU @ 3.40GHz×8.
>
> ===================================================
> ||  instr  ||  helper  ||    tcg    ||   hybrid  ||
> ===================================================
> || ilvr.b: || 62.87 ms ||  74.76 ms ||  61.52 ms || <-- helper
> || ilvr.h: || 44.11 ms ||  33.00 ms ||  33.55 ms || <-- tcg
> || ilvr.w: || 34.97 ms ||  23.06 ms ||  22.67 ms || <-- tcg
> || ilvr.d: || 27.33 ms ||  19.87 ms ||  20.02 ms || <-- tcg
> ===================================================
>

instr -> instruction

||  61.52 ms || <-- helper  ->  ||  61.52 ms (helper) ||

and similar for other three raws.

> Signed-off-by: Mateja Marjanovic <mateja.marjanovic@rt-rk.com>
> ---
>  target/mips/helper.h     |   2 +-
>  target/mips/msa_helper.c |  33 +++++++++++----
>  target/mips/translate.c  | 107 ++++++++++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 132 insertions(+), 10 deletions(-)
>
> diff --git a/target/mips/helper.h b/target/mips/helper.h
> index cd73723..d4755ef 100644
> --- a/target/mips/helper.h
> +++ b/target/mips/helper.h
> @@ -862,7 +862,6 @@ DEF_HELPER_5(msa_sld_df, void, env, i32, i32, i32, i32)
>  DEF_HELPER_5(msa_splat_df, void, env, i32, i32, i32, i32)
>  DEF_HELPER_5(msa_pckev_df, void, env, i32, i32, i32, i32)
>  DEF_HELPER_5(msa_pckod_df, void, env, i32, i32, i32, i32)
> -DEF_HELPER_5(msa_ilvr_df, void, env, i32, i32, i32, i32)
>  DEF_HELPER_5(msa_vshf_df, void, env, i32, i32, i32, i32)
>  DEF_HELPER_5(msa_srar_df, void, env, i32, i32, i32, i32)
>  DEF_HELPER_5(msa_srlr_df, void, env, i32, i32, i32, i32)
> @@ -946,6 +945,7 @@ DEF_HELPER_4(msa_insert_w, void, env, i32, i32, i32)
>  DEF_HELPER_4(msa_insert_d, void, env, i32, i32, i32)
>
>  DEF_HELPER_4(msa_ilvl_b, void, env, i32, i32, i32)
> +DEF_HELPER_4(msa_ilvr_b, void, env, i32, i32, i32)
>
>  DEF_HELPER_4(msa_fclass_df, void, env, i32, i32, i32)
>  DEF_HELPER_4(msa_ftrunc_s_df, void, env, i32, i32, i32)
> diff --git a/target/mips/msa_helper.c b/target/mips/msa_helper.c
> index 84bbe6f..2470cef 100644
> --- a/target/mips/msa_helper.c
> +++ b/target/mips/msa_helper.c
> @@ -1181,14 +1181,6 @@ MSA_FN_DF(pckev_df)
>      } while (0)
>  MSA_FN_DF(pckod_df)
>  #undef MSA_DO
> -
> -#define MSA_DO(DF)                      \
> -    do {                                \
> -        pwx->DF[2*i]   = R##DF(pwt, i); \
> -        pwx->DF[2*i+1] = R##DF(pws, i); \
> -    } while (0)
> -MSA_FN_DF(ilvr_df)
> -#undef MSA_DO
>  #undef MSA_LOOP_COND
>
>  #define MSA_LOOP_COND(DF) \
> @@ -1249,6 +1241,31 @@ void helper_msa_ilvl_b(CPUMIPSState *env, uint32_t wd,
>      pwd->b[15] = pws->b[15];
>  }
>
> +void helper_msa_ilvr_b(CPUMIPSState *env, uint32_t wd,
> +                       uint32_t ws, uint32_t wt)
> +{
> +    wr_t *pwd = &(env->active_fpu.fpr[wd].wr);
> +    wr_t *pws = &(env->active_fpu.fpr[ws].wr);
> +    wr_t *pwt = &(env->active_fpu.fpr[wt].wr);
> +

Why do we use here env->active_fpu.fpr[wd].wr, while for other instructions in
this patch, we access msa_wr_d<b|h|w|d[] directly?

> +    pwd->b[15] = pws->b[7];
> +    pwd->b[14] = pwt->b[7];
> +    pwd->b[13] = pws->b[6];
> +    pwd->b[12] = pwt->b[6];
> +    pwd->b[11] = pws->b[5];
> +    pwd->b[10] = pwt->b[5];
> +    pwd->b[9]  = pws->b[4];
> +    pwd->b[8]  = pwt->b[4];
> +    pwd->b[7]  = pws->b[3];
> +    pwd->b[6]  = pwt->b[3];
> +    pwd->b[5]  = pws->b[2];
> +    pwd->b[4]  = pwt->b[2];
> +    pwd->b[3]  = pws->b[1];
> +    pwd->b[2]  = pwt->b[1];
> +    pwd->b[1]  = pws->b[0];
> +    pwd->b[0]  = pwt->b[0];
> +}
> +
>  void helper_msa_copy_s_b(CPUMIPSState *env, uint32_t rd,
>                           uint32_t ws, uint32_t n)
>  {
> diff --git a/target/mips/translate.c b/target/mips/translate.c
> index 6c6811e..90332fb 100644
> --- a/target/mips/translate.c
> +++ b/target/mips/translate.c
> @@ -28885,6 +28885,96 @@ static void gen_msa_bit(CPUMIPSState *env, DisasContext *ctx)
>  }
>
>  /*
> + * [MSA] ILVR.H wd, ws, wt
> + *
> + *   Vector Interleave Right (halfword data elements)
> + *
> + */
> +static inline void gen_ilvr_h(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 = 0x000000000000ffffULL;
> +
> +    tcg_gen_andi_i64(t1, msa_wr_d[wt * 2], mask);
> +    tcg_gen_mov_i64(t2, t1);
> +    tcg_gen_andi_i64(t1, msa_wr_d[ws * 2], mask);
> +    tcg_gen_shli_i64(t1, t1, 16);
> +    tcg_gen_or_i64(t2, t2, t1);
> +
> +    mask <<= 16;
> +    tcg_gen_andi_i64(t1, msa_wr_d[wt * 2], mask);
> +    tcg_gen_shli_i64(t1, t1, 16);
> +    tcg_gen_or_i64(t2, t2, t1);
> +    tcg_gen_andi_i64(t1, msa_wr_d[ws * 2], mask);
> +    tcg_gen_shli_i64(t1, t1, 32);
> +    tcg_gen_or_i64(msa_wr_d[wd * 2], t2, t1);
> +
> +    mask <<= 16;
> +    tcg_gen_andi_i64(t1, msa_wr_d[wt * 2], mask);
> +    tcg_gen_shri_i64(t1, t1, 32);
> +    tcg_gen_mov_i64(t2, t1);
> +    tcg_gen_andi_i64(t1, msa_wr_d[ws * 2], mask);
> +    tcg_gen_shri_i64(t1, t1, 16);
> +    tcg_gen_or_i64(t2, t2, t1);
> +
> +    mask <<= 16;
> +    tcg_gen_andi_i64(t1, msa_wr_d[wt * 2], mask);
> +    tcg_gen_shri_i64(t1, t1, 16);
> +    tcg_gen_or_i64(t2, t2, t1);
> +    tcg_gen_andi_i64(t1, msa_wr_d[ws * 2], mask);
> +    tcg_gen_or_i64(msa_wr_d[wd * 2 + 1], t2, t1);
> +
> +    tcg_temp_free_i64(t1);
> +    tcg_temp_free_i64(t2);
> +}
> +
> +/*
> + * [MSA] ILVR.W wd, ws, wt
> + *
> + *   Vector Interleave Right (word data elements)
> + *
> + */
> +static inline void gen_ilvr_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;

Use tcg_const_i64(). The same for the previous function.

> +
> +    tcg_gen_andi_i64(t1, msa_wr_d[wt * 2], mask);
> +    tcg_gen_mov_i64(t2, t1);
> +    tcg_gen_andi_i64(t1, msa_wr_d[ws * 2], mask);
> +    tcg_gen_shli_i64(t1, t1, 32);
> +    tcg_gen_or_i64(msa_wr_d[wd * 2], t2, t1);
> +
> +    mask <<= 32;

Just assign the constant value to the mask, no need for shift operation.
The same applies for other similar cases in this patch.

> +    tcg_gen_andi_i64(t1, msa_wr_d[wt * 2], mask);
> +    tcg_gen_shri_i64(t1, t1, 32);
> +    tcg_gen_mov_i64(t2, t1);
> +    tcg_gen_andi_i64(t1, msa_wr_d[ws * 2], mask);
> +    tcg_gen_or_i64(msa_wr_d[wd * 2 + 1], t2, t1);
> +
> +    tcg_temp_free_i64(t1);
> +    tcg_temp_free_i64(t2);
> +}
> +
> +/*
> + * [MSA] ILVR.D wd, ws, wt
> + *
> + *   Vector Interleave Right (doubleword data elements)
> + *
> + */
> +static inline void gen_ilvr_d(CPUMIPSState *env, uint32_t wd,
> +                              uint32_t ws, uint32_t wt)
> +{
> +    tcg_gen_mov_i64(msa_wr_d[wd * 2 + 1], msa_wr_d[ws * 2]);
> +    tcg_gen_mov_i64(msa_wr_d[wd * 2], msa_wr_d[wt * 2]);
> +}
> +

This function seems to be identical to the gen_ilvev_d(). Please,
if that is the case, in this patch rename gen_ilvev_d() to gen_ilvev_ilvr_d(),
and  use it both for hanlding ILVEV.D and ILVR.D.

> +
> +/*
>   * [MSA] ILVL.B wd, ws, wt
>   *
>   *   Vector Interleave Left (byte data elements)
> @@ -29380,7 +29470,22 @@ static void gen_msa_3r(CPUMIPSState *env, DisasContext *ctx)
>          gen_helper_msa_div_u_df(cpu_env, tdf, twd, tws, twt);
>          break;
>      case OPC_ILVR_df:
> -        gen_helper_msa_ilvr_df(cpu_env, tdf, twd, tws, twt);
> +        switch (df) {
> +        case DF_BYTE:
> +            gen_helper_msa_ilvr_b(cpu_env, twd, tws, twt);
> +            break;
> +        case DF_HALF:
> +            gen_ilvr_h(env, wd, ws, wt);
> +            break;
> +        case DF_WORD:
> +            gen_ilvr_w(env, wd, ws, wt);
> +            break;
> +        case DF_DOUBLE:
> +            gen_ilvr_d(env, wd, ws, wt);
> +            break;
> +        default:
> +            assert(0);
> +        }
>          break;
>      case OPC_BINSL_df:
>          gen_helper_msa_binsl_df(cpu_env, tdf, twd, tws, twt);
> --
> 2.7.4
>
>

Thanks,
Aleksandar