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Re: [RFC PATCH v1 07/43] tcg: Increase maximum TB size and maximum tempo


From: Richard Henderson
Subject: Re: [RFC PATCH v1 07/43] tcg: Increase maximum TB size and maximum temporaries
Date: Fri, 22 Nov 2024 12:11:12 -0600
User-agent: Mozilla Thunderbird

On 11/20/24 19:49, Anton Johansson wrote:
Doubles amount of space allocated for translation blocks.  This is
needed, particularly for Hexagon, where a single instruction packet may
consist of up to four vector instructions.  If each vector instruction
then gets expanded into gvec operations that utilize a small host vector
size the TB blows up quite quickly.

Signed-off-by: Anton Johansson <anjo@rev.ng>
I hope this is a performance modification only?
I hope that the normal set of "restart on resource overflow" code functioned 
correctly?
If you're overflowing these values with a single hexagon insn, then I suggest something is wrong.
---
  include/tcg/tcg.h | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/tcg/tcg.h b/include/tcg/tcg.h
index d3e820568f..bd8cb9ff50 100644
--- a/include/tcg/tcg.h
+++ b/include/tcg/tcg.h
@@ -39,7 +39,7 @@
  /* XXX: make safe guess about sizes */
  #define MAX_OP_PER_INSTR 266
-#define CPU_TEMP_BUF_NLONGS 128
+#define CPU_TEMP_BUF_NLONGS 256
  #define TCG_STATIC_FRAME_SIZE  (CPU_TEMP_BUF_NLONGS * sizeof(long))
Changing this probably requires auditing all tcg/arch/ backends.  The various prologue 
generation code *ought* to catch out of range values, but I bet we weren't that careful.

r~

#if TCG_TARGET_REG_BITS == 32
@@ -231,7 +231,7 @@ typedef struct TCGPool {
#define TCG_POOL_CHUNK_SIZE 32768 -#define TCG_MAX_TEMPS 512
+#define TCG_MAX_TEMPS 1024
  #define TCG_MAX_INSNS 512
/* when the size of the arguments of a called function is smaller than



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