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Re: Faster compilation speed
On Wed, Aug 14, 2002 at 01:14:53PM -0400, David Edelsohn wrote:
> Thanks for the suggestion. I think the results I got are pretty damning...
Try the following. Appears to cut 30 seconds (3.5%) off of an -O2 -g
build of reload.c, and a small fraction of a second (3.1%) at -O0 -g.
This on an 800MHz Pentium III (Coppermine).
If I have rest_of_compilation dump out insn addresses before
optimization (the only time we could even hope for relatively
sequential nodes), INSN nodes are indeed largely coherent
(even without this patch). But NOTE nodes are smaller, and
get put in a different size bucket, and so are allocated from
different pages. Padding out the size of NOTEs and BARRIERs
make them allocated from the same pages, and the resulting
initial addresses are about as sequential as one could hope.
The remaining main source of non-sequentiality in the initial rtl is
label = gen_label_rtx ();
/* emit code */
emit_label (label);
and there's really no helping that.
The other change is to add allocation buckets for two
important rtx sizes. On 32-bit systems, two-operand rtxs
(including REG, MEM, PLUS, etc) are 12 bytes, but we were
allocating 16 bytes. Similarly an INSN (9 operand) and
CALL_INSN (10 operand) are 40 and 44 bytes respectively
but we were allocating 64. I choose to put the bucket
at 10 operand so that CALL_INSNs and JUMP_INSNs can fit.
I havn't measured the overall real-life memory savings,
but this is 25% for REGs and 30% for INSNs.
r~
* ggc-page.c (RTL_SIZE): New.
(extra_order_size_table): Add specializations for 2 and 10 rtl slots.
* rtl.def (BARRIER, NOTE): Pad to 9 slots.
Index: ggc-page.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/ggc-page.c,v
retrieving revision 1.51
diff -c -p -d -r1.51 ggc-page.c
*** ggc-page.c 4 Jun 2002 11:30:36 -0000 1.51
--- ggc-page.c 14 Aug 2002 22:38:57 -0000
*************** Software Foundation, 59 Temple Place - S
*** 163,175 ****
#define NUM_EXTRA_ORDERS ARRAY_SIZE (extra_order_size_table)
/* The Ith entry is the maximum size of an object to be stored in the
Ith extra order. Adding a new entry to this array is the *only*
thing you need to do to add a new special allocation size. */
static const size_t extra_order_size_table[] = {
sizeof (struct tree_decl),
! sizeof (struct tree_list)
};
/* The total number of orders. */
--- 163,180 ----
#define NUM_EXTRA_ORDERS ARRAY_SIZE (extra_order_size_table)
+ #define RTL_SIZE(NSLOTS) \
+ (sizeof (struct rtx_def) + ((NSLOTS) - 1) * sizeof (rtunion))
+
/* The Ith entry is the maximum size of an object to be stored in the
Ith extra order. Adding a new entry to this array is the *only*
thing you need to do to add a new special allocation size. */
static const size_t extra_order_size_table[] = {
sizeof (struct tree_decl),
! sizeof (struct tree_list),
! RTL_SIZE (2), /* REG, MEM, PLUS, etc. */
! RTL_SIZE (10), /* INSN, CALL_INSN, JUMP_INSN */
};
/* The total number of orders. */
Index: rtl.def
===================================================================
RCS file: /cvs/gcc/gcc/gcc/rtl.def,v
retrieving revision 1.58
diff -c -p -d -r1.58 rtl.def
*** rtl.def 19 Jul 2002 23:11:18 -0000 1.58
--- rtl.def 14 Aug 2002 22:38:57 -0000
*************** DEF_RTL_EXPR(JUMP_INSN, "jump_insn", "iu
*** 566,587 ****
DEF_RTL_EXPR(CALL_INSN, "call_insn", "iuuBteieee", 'i')
/* A marker that indicates that control will not flow through. */
! DEF_RTL_EXPR(BARRIER, "barrier", "iuu", 'x')
/* Holds a label that is followed by instructions.
Operand:
! 4: is used in jump.c for the use-count of the label.
! 5: is used in flow.c to point to the chain of label_ref's to this label.
! 6: is a number that is unique in the entire compilation.
! 7: is the user-given name of the label, if any. */
DEF_RTL_EXPR(CODE_LABEL, "code_label", "iuuB00is", 'x')
/* Say where in the code a source line starts, for symbol table's sake.
Operand:
! 4: filename, if line number > 0, note-specific data otherwise.
! 5: line number if > 0, enum note_insn otherwise.
! 6: unique number if line number == note_insn_deleted_label. */
! DEF_RTL_EXPR(NOTE, "note", "iuuB0ni", 'x')
/* ----------------------------------------------------------------------
Top level constituents of INSN, JUMP_INSN and CALL_INSN.
--- 566,589 ----
DEF_RTL_EXPR(CALL_INSN, "call_insn", "iuuBteieee", 'i')
/* A marker that indicates that control will not flow through. */
! DEF_RTL_EXPR(BARRIER, "barrier", "iuu000000", 'x')
/* Holds a label that is followed by instructions.
Operand:
! 5: is used in jump.c for the use-count of the label.
! 6: is used in flow.c to point to the chain of label_ref's to this label.
! 7: is a number that is unique in the entire compilation.
! 8: is the user-given name of the label, if any. */
DEF_RTL_EXPR(CODE_LABEL, "code_label", "iuuB00is", 'x')
/* Say where in the code a source line starts, for symbol table's sake.
Operand:
! 5: filename, if line number > 0, note-specific data otherwise.
! 6: line number if > 0, enum note_insn otherwise.
! 7: unique number if line number == note_insn_deleted_label.
! 8-9: padding so that notes and insns are the same size, and thus
! allocated from the same page ordering. */
! DEF_RTL_EXPR(NOTE, "note", "iuuB0ni00", 'x')
/* ----------------------------------------------------------------------
Top level constituents of INSN, JUMP_INSN and CALL_INSN.