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Re: [Qemu-devel] [PATCH v6 2/4] target/mips: Optimize ILVEV.<B|H|W|D> MS


From: Mateja Marjanovic
Subject: Re: [Qemu-devel] [PATCH v6 2/4] target/mips: Optimize ILVEV.<B|H|W|D> MSA instructions
Date: Mon, 15 Apr 2019 15:48:01 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1


On 13.4.19. 18:05, Aleksandar Markovic wrote:
On Thu, Apr 4, 2019 at 3:18 PM Mateja Marjanovic
<address@hidden> 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 the solution
which is implemented in this patch.

Performance measurement is done by executing the
instructions a large number of times on a computer
What is the exact number of times?
I will add that from now on.

with Intel Core i7-3770 CPU @ 3.40GHz×8.

============================================================
|| instr    ||   before    || no-deposit ||  with-deposit ||
============================================================
|| ilvev.b  ||  126.92 ms  ||  24.52 ms  ||   24.43 ms    ||
|| ilvev.h  ||   93.67 ms  ||  23.92 ms  ||   23.86 ms    ||
|| ilvev.w  ||  117.86 ms  ||  23.83 ms  ||   22.17 ms    ||
|| ilvev.d  ||   45.49 ms  ||  19.74 ms  ||   19.71 ms    ||
============================================================

"With-deposit" for ilvev.w can't be the same as in the previous
version (22.17 ms), since you eliminated one tcg_gen_andi_i64() in
this version compared to the previous one. "With-deposit" for ilvev.wb
and ilvev.h also can't be the same. It looks you just copy-pasted the
numbers. Please retest the performance and attach the accurate
numbers.
My mistake, I will add it in v7.

Also, there should be five columns and their meanings should be:

   - instruction
   - before
   - no-deposit-no-mask-as-tcg-constant
   - with-deposit-no-mask-as-tcg-constant
   - with-deposit-with-mask-as-tcg-constant (final)
Alright, but the deposit function and mask as a tcg constant
are optimizations for two different problems. The deposit
function is used only in case of word, and mask as a tcg
constant in halfword and byte.
No-deposit column and with-deposit column have the
same statistical values in every row, except ILVEV.W,
which is the only function which uses the deposit
function.

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: Richard Henderson <address@hidden>
You forgot Philippe.
I will add Philippe, ofcourse.

Signed-off-by: Mateja Marjanovic <address@hidden>
---
  target/mips/helper.h     |   1 -
  target/mips/msa_helper.c |   9 -----
  target/mips/translate.c  | 101 ++++++++++++++++++++++++++++++++++++++++++++++-
  3 files changed, 100 insertions(+), 11 deletions(-)

diff --git a/target/mips/helper.h b/target/mips/helper.h
index 02e16c7..82f6a40 100644
--- a/target/mips/helper.h
+++ b/target/mips/helper.h
@@ -864,7 +864,6 @@ 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_ilvl_df, void, env, i32, i32, i32, i32)
  DEF_HELPER_5(msa_ilvr_df, void, env, i32, i32, i32, i32)
-DEF_HELPER_5(msa_ilvev_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)
diff --git a/target/mips/msa_helper.c b/target/mips/msa_helper.c
index a7ea6aa..d5c3842 100644
--- a/target/mips/msa_helper.c
+++ b/target/mips/msa_helper.c
@@ -1197,15 +1197,6 @@ MSA_FN_DF(ilvl_df)
      } while (0)
  MSA_FN_DF(ilvr_df)
  #undef MSA_DO
-
-#define MSA_DO(DF)                      \
-    do {                                \
-        pwx->DF[2*i]   = pwt->DF[2*i];  \
-        pwx->DF[2*i+1] = pws->DF[2*i];  \
-    } while (0)
-MSA_FN_DF(ilvev_df)
-#undef MSA_DO
-
  #undef MSA_LOOP_COND

  #define MSA_LOOP_COND(DF) \
diff --git a/target/mips/translate.c b/target/mips/translate.c
index df685e4..3057669 100644
--- a/target/mips/translate.c
+++ b/target/mips/translate.c
@@ -28973,6 +28973,90 @@ static inline void gen_ilvod_d(CPUMIPSState *env, 
uint32_t wd,
      tcg_gen_mov_i64(msa_wr_d[wd * 2 + 1], msa_wr_d[ws * 2 + 1]);
  }

+/*
+ * [MSA] ILVEV.B wd, ws, wt
+ *
+ *   Vector Interleave Even (byte data elements)
+ *
+ */
+static inline void gen_ilvev_b(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();
+    TCGv_i64 mask = tcg_const_i64(0x00ff00ff00ff00ffULL);
+
+    tcg_gen_and_i64(t1, msa_wr_d[wt * 2], mask);
+    tcg_gen_and_i64(t2, msa_wr_d[ws * 2], mask);
+    tcg_gen_shli_i64(t2, t2, 8);
+    tcg_gen_or_i64(msa_wr_d[wd * 2], t1, t2);
+
+    tcg_gen_and_i64(t1, msa_wr_d[wt * 2 + 1], mask);
+    tcg_gen_and_i64(t2, msa_wr_d[ws * 2 + 1], mask);
+    tcg_gen_shli_i64(t2, t2, 8);
+    tcg_gen_or_i64(msa_wr_d[wd * 2 + 1], t1, t2);
+
+    tcg_temp_free_i64(mask);
+    tcg_temp_free_i64(t1);
+    tcg_temp_free_i64(t2);
+}
+
+/*
+ * [MSA] ILVEV.H wd, ws, wt
+ *
+ *   Vector Interleave Even (halfword data elements)
+ *
+ */
+static inline void gen_ilvev_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();
+    TCGv_i64 mask = tcg_const_i64(0x0000ffff0000ffffULL);
+
+    tcg_gen_and_i64(t1, msa_wr_d[wt * 2], mask);
+    tcg_gen_and_i64(t2, msa_wr_d[ws * 2], mask);
+    tcg_gen_shli_i64(t2, t2, 16);
+    tcg_gen_or_i64(msa_wr_d[wd * 2], t1, t2);
+
+    tcg_gen_and_i64(t1, msa_wr_d[wt * 2 + 1], mask);
+    tcg_gen_and_i64(t2, msa_wr_d[ws * 2 + 1], mask);
+    tcg_gen_shli_i64(t2, t2, 16);
+    tcg_gen_or_i64(msa_wr_d[wd * 2 + 1], t1, t2);
+
+    tcg_temp_free_i64(mask);
+    tcg_temp_free_i64(t1);
+    tcg_temp_free_i64(t2);
+}
Please apply Philippe's refactoring for the preceding two functions.
I will in v7.

+
+/*
+ * [MSA] ILVEV.W wd, ws, wt
+ *
+ *   Vector Interleave Even (word data elements)
+ *
+ */
+static inline void gen_ilvev_w(CPUMIPSState *env, uint32_t wd,
+                               uint32_t ws, uint32_t wt)
+{
+    tcg_gen_deposit_i64(msa_wr_d[wd * 2], msa_wr_d[wt * 2],
+                        msa_wr_d[ws * 2], 32, 32);
+    tcg_gen_deposit_i64(msa_wr_d[wd * 2 + 1], msa_wr_d[wt * 2 + 1],
+                        msa_wr_d[ws * 2 + 1], 32, 32);
+}
+
+/*
+ * [MSA] ILVEV.D wd, ws, wt
+ *
+ *   Vector Interleave Even (Doubleword data elements)
Doubleword -> doubleword
It will be changed in v7.

+ *
+ */
+static inline void gen_ilvev_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]);
+}
+
  static void gen_msa_3r(CPUMIPSState *env, DisasContext *ctx)
  {
  #define MASK_MSA_3R(op)    (MASK_MSA_MINOR(op) | (op & (0x7 << 23)))
@@ -29129,7 +29213,22 @@ static void gen_msa_3r(CPUMIPSState *env, DisasContext 
*ctx)
          gen_helper_msa_mod_s_df(cpu_env, tdf, twd, tws, twt);
          break;
      case OPC_ILVEV_df:
-        gen_helper_msa_ilvev_df(cpu_env, tdf, twd, tws, twt);
+        switch (df) {
+        case DF_BYTE:
+            gen_ilvev_b(env, wd, ws, wt);
+            break;
+        case DF_HALF:
+            gen_ilvev_h(env, wd, ws, wt);
+            break;
+        case DF_WORD:
+            gen_ilvev_w(env, wd, ws, wt);
+            break;
+        case DF_DOUBLE:
+            gen_ilvev_d(env, wd, ws, wt);
+            break;
+        default:
+            assert(0);
+        }
          break;
      case OPC_BINSR_df:
          gen_helper_msa_binsr_df(cpu_env, tdf, twd, tws, twt);
--
2.7.4


Thanks,
Aleksandar
Thanks,
Mateja



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