11:31 a.m.
PATCH 21.5
This change improves performance for VM with large folder a little, though
it’s not a complete solution. In particular, when hitting q in a modified
folder with index files turned on and non-ASCII bytes in the buffer,
#'vm-sort-compare-physical-order is called about 5 N times for N messages,
giving 10 N calls to marker-position, which is expensive.
This shows up as char-byte conversion in XEmacs profiling, and my below
change improves this, such that the majority of the time in the described
context is now in #'write-file-internal, not char-byte conversion.
diff -r 4e69b24a2301 src/bytecode.c
--- a/src/bytecode.c Mon Oct 28 16:03:53 2013 +0100
+++ b/src/bytecode.c Sun Dec 01 11:16:59 2013 +0000
＠＠ -287,7 +287,7 ＠＠
bytecode_arithcompare (Lisp_Object obj1, Lisp_Object obj2)
{
#ifdef WITH_NUMBER_TYPES
- switch (promote_args (&obj1, &obj2))
+ switch (promote_args_lazy (&obj1, &obj2))
{
case FIXNUM_T:
{
＠＠ -306,6 +306,13 ＠＠
case BIGFLOAT_T:
return bigfloat_cmp (XBIGFLOAT_DATA (obj1), XBIGFLOAT_DATA (obj2));
#endif
+ case MARKER_T:
+ {
+ Bytebpos ival1 = byte_marker_position (obj1);
+ Bytebpos ival2 = byte_marker_position (obj2);
+ return ival1 < ival2 ? -1 : ival1 > ival2 ? 1 : 0;
+ }
+
default: /* FLOAT_T */
{
double dval1 = XFLOAT_DATA (obj1), dval2 = XFLOAT_DATA (obj2);
＠＠ -320,7 +327,19 ＠＠
if (FIXNUMP (obj1)) ival1 = XFIXNUM (obj1);
else if (CHARP (obj1)) ival1 = XCHAR (obj1);
- else if (MARKERP (obj1)) ival1 = marker_position (obj1);
+ else if (MARKERP (obj1))
+ {
+ /* Handle markers specially, since #'marker-position can be O(N): */
+ if (MARKERP (obj2)
+ && (XMARKER (obj1)->buffer == XMARKER (obj2)->buffer))
+ {
+ Bytebpos ival1 = byte_marker_position (obj1);
+ Bytebpos ival2 = byte_marker_position (obj2);
+ return ival1 < ival2 ? -1 : ival1 > ival2 ? 1 : 0;
+ }
+
+ ival1 = marker_position (obj1);
+ }
else goto arithcompare_float;
if (FIXNUMP (obj2)) ival2 = XFIXNUM (obj2);
diff -r 4e69b24a2301 src/data.c
--- a/src/data.c Mon Oct 28 16:03:53 2013 +0100
+++ b/src/data.c Sun Dec 01 11:16:59 2013 +0000
＠＠ -936,10 +936,10 ＠＠
{ \
obj1 = args[i - 1]; \
obj2 = args[i]; \
- switch (promote_args (&obj1, &obj2)) \
+ switch (promote_args_lazy (&obj1, &obj2)) \
{ \
case FIXNUM_T: \
- if (!(XREALFIXNUM (obj1) c_op XREALFIXNUM (obj2))) \
+ if (!(XREALFIXNUM (obj1) c_op XREALFIXNUM (obj2))) \
return Qnil; \
break; \
BIGNUM_CASE (op) \
＠＠ -949,11 +949,20 ＠＠
return Qnil; \
break; \
BIGFLOAT_CASE (op) \
+ case MARKER_T: \
+ if (!(byte_marker_position (obj1) c_op \
+ byte_marker_position (obj2))) \
+ return Qnil; \
+ break; \
} \
} \
return Qt; \
}
#else /* !WITH_NUMBER_TYPES */
+/* We don't convert markers lazily here, although we could. It's more
+ important that we do this lazily in bytecode, which is the case; see
+ bytecode_arithcompare().
+ */
#define ARITHCOMPARE_MANY(c_op,op) \
{ \
int_or_double iod1, iod2, *p = &iod1, *q = &iod2; \
diff -r 4e69b24a2301 src/number.h
--- a/src/number.h Mon Oct 28 16:03:53 2013 +0100
+++ b/src/number.h Sun Dec 01 11:16:59 2013 +0000
＠＠ -373,11 +373,40 ＠＠
EXFUN (Fcanonicalize_number, 1);
-enum number_type {FIXNUM_T, BIGNUM_T, RATIO_T, FLOAT_T, BIGFLOAT_T};
+#define NUMBER_TYPES(prefix) prefix##FIXNUM_T, prefix##BIGNUM_T, \
+ prefix##RATIO_T, prefix##FLOAT_T, prefix##BIGFLOAT_T
+
+enum number_type { NUMBER_TYPES() };
+enum lazy_number_type { NUMBER_TYPES(LAZY_), MARKER_T };
extern enum number_type get_number_type (Lisp_Object);
extern enum number_type promote_args (Lisp_Object *, Lisp_Object *);
+/* promote_args() *always* converts a marker argument to an integer.
+
+ Unfortunately, for a marker with byte position N, getting the (character)
+ marker position is O(N). Getting the character position isn't necessary
+ for bytecode_arithcompare() if two markers being compared are in the same
+ buffer, comparing the byte position is enough.
+
+ It is necessary for those operations implemented by bytecode_arithop(),
+ though, with the exception that Bmax and Bmin could be changed to call
+ marker-position once rather than twice. */
+DECLARE_INLINE_HEADER (
+enum lazy_number_type
+promote_args_lazy (Lisp_Object *obj1, Lisp_Object *obj2))
+{
+ if (MARKERP (*obj1) && MARKERP (*obj2) &&
+ XMARKER (*obj1)->buffer == XMARKER (*obj2)->buffer)
+ {
+ return MARKER_T;
+ }
+
+ return (enum lazy_number_type) promote_args (obj1, obj2);
+}
+
+#undef NUMBER_TYPES
+
#ifdef WITH_NUMBER_TYPES
DECLARE_INLINE_HEADER (
int
--
‘Liston operated so fast that he once accidentally amputated an assistant’s
fingers along with a patient’s leg, […] The patient and the assistant both
died of sepsis, and a spectator reportedly died of shock, resulting in the
only known procedure with a 300% mortality.’ (Atul Gawande, NEJM, 2012)
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