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* gprof.c (long_options): Add "--function-ordering" and

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"--file-ordering" options.
	(usage): Add new options to usage message.
	(main): Handle new options.
	* gprof.h (STYLE_FUNCTION_ORDER): Define.
	(STYLE_FILE_ORDER): Define.
	(function_mapping_file): Declare.
	* cg_arcs.c (arcs, numarcs): New globals.
	(arc_add): Put new arcs into the arc array so the function/file
	ordering code can examine them.
	* cg_arcs.h (struct arc): New field "has_been_placed".
	(arcs, numarcs): Declare new globals.
	* core.c (symbol_map, symbol_map_count): New globals.
	(read_function_mappings): New function to read in a function
	to object map file.
	(core_init): Call read_function_mappings if a function mapping
	file exists.
	(core_create_function_syms): Handle function to object file
	mappings.
	* symtab.h (struct sym): New fields "mapped", "has_been_placed",
	"nuses", "prev".
	* cg_print.c (cmp_arc_count): New function for sorting arcs.
	(cmp_fun_nuses): Likewise for functions.
	(cg_print_function_ordering): New function to print a suggested
	function ordering.
	(cg_print_file_ordering): Likewise for ordering .o files.
	(order_and_dump_functions_by_arcs): Helper function for function
	and object file ordering code.
Gprof changes for mentor vm work.
This commit is contained in:
Jeff Law
1995-12-31 06:36:30 +00:00
parent 71128bd7a9
commit 64c50fc5db
9 changed files with 908 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

616
gprof/cg_print.c
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@@ -11,6 +11,9 @@
#define EQUALTO 0
#define GREATERTHAN 1
static void order_and_dump_functions_by_arcs PARAMS ((Arc **, unsigned long,
int, Arc **,
unsigned long *));
/* declarations of automatically generated functions to output blurbs: */
extern void bsd_callg_blurb PARAMS ((FILE * fp));
extern void fsf_callg_blurb PARAMS ((FILE * fp));
@@ -654,3 +657,616 @@ DEFUN_VOID (cg_print_index)
}
free (name_sorted_syms);
}
/* Compare two arcs based on their usage counts. We want to sort
in descending order. */
static int
DEFUN (cmp_arc_count, (left, right), const PTR left AND const PTR right)
{
const Arc **npp1 = (const Arc **) left;
const Arc **npp2 = (const Arc **) right;
if ((*npp1)->count > (*npp2)->count)
return -1;
else if ((*npp1)->count < (*npp2)->count)
return 1;
else
return 0;
}
/* Compare two funtions based on their usage counts. We want to sort
in descending order. */
static int
DEFUN (cmp_fun_nuses, (left, right), const PTR left AND const PTR right)
{
const Sym **npp1 = (const Sym **) left;
const Sym **npp2 = (const Sym **) right;
if ((*npp1)->nuses > (*npp2)->nuses)
return -1;
else if ((*npp1)->nuses < (*npp2)->nuses)
return 1;
else
return 0;
}
/* Print a suggested function ordering based on the profiling data.
We perform 4 major steps when ordering functions:
* Group unused functions together and place them at the
end of the function order.
* Search the highest use arcs (those which account for 90% of
the total arc count) for functions which have several parents.
Group those with the most call sites together (currently the
top 1.25% which have at least five different call sites).
These are emitted at the start of the function order.
* Use a greedy placement algorithm to place functions which
occur in the top 99% of the arcs in the profile. Some provisions
are made to handle high usage arcs where the parent and/or
child has already been placed.
* Run the same greedy placement algorithm on the remaining
arcs to place the leftover functions.
The various "magic numbers" should (one day) be tuneable by command
line options. They were arrived at by benchmarking a few applications
with various values to see which values produced better overall function
orderings.
Of course, profiling errors, machine limitations (PA long calls), and
poor cutoff values for the placement algorithm may limit the usefullness
of the resulting function order. Improvements would be greatly appreciated.
Suggestions:
* Place the functions with many callers near the middle of the
list to reduce long calls.
* Propagate arc usage changes as functions are placed. Ie if
func1 and func2 are placed together, arcs to/from those arcs
to the same parent/child should be combined, then resort the
arcs to choose the next one.
* Implement some global positioning algorithm to place the
chains made by the greedy local positioning algorithm. Probably
by examining arcs which haven't been placed yet to tie two
chains together.
* Take a function's size and time into account in the algorithm;
size in particular is important on the PA (long calls). Placing
many small functions onto their own page may be wise.
* Use better profiling information; many published algorithms
are based on call sequences through time, rather than just
arc counts.
* Prodecure cloning could improve performance when a small number
of arcs account for most of the calls to a particular function.
* Use relocation information to avoid moving unused functions
completely out of the code stream; this would avoid severe lossage
when the profile data bears little resemblance to actual runs.
* Propagation of arc usages should also improve .o link line
ordering which shares the same arc placement algorithm with
the function ordering code (in fact it is a degenerate case
of function ordering). */
void
DEFUN_VOID (cg_print_function_ordering)
{
unsigned long index, used, unused, scratch_index;
unsigned long unplaced_arc_count, high_arc_count, scratch_arc_count;
#ifdef __GNU_C__
unsigned long long total_arcs, tmp_arcs_count;
#else
unsigned long total_arcs, tmp_arcs_count;
#endif
Sym **unused_syms, **used_syms, **scratch_syms;
Arc **unplaced_arcs, **high_arcs, **scratch_arcs;
index = 0;
used = 0;
unused = 0;
scratch_index = 0;
unplaced_arc_count = 0;
high_arc_count = 0;
scratch_arc_count = 0;
/* First group all the unused functions together. */
unused_syms = (Sym **) xmalloc (symtab.len * sizeof (Sym *));
used_syms = (Sym **) xmalloc (symtab.len * sizeof (Sym *));
scratch_syms = (Sym **) xmalloc (symtab.len * sizeof (Sym *));
high_arcs = (Arc **) xmalloc (numarcs * sizeof (Arc *));
scratch_arcs = (Arc **) xmalloc (numarcs * sizeof (Arc *));
unplaced_arcs = (Arc **) xmalloc (numarcs * sizeof (Arc *));
/* Walk through all the functions; mark those which are never
called as placed (we'll emit them as a group later). */
for (index = 0, used = 0, unused = 0; index < symtab.len; index++)
{
if (symtab.base[index].ncalls == 0)
{
/* Filter out gprof generated names. */
if (strcmp (symtab.base[index].name, "<locore>")
&& strcmp (symtab.base[index].name, "<hicore>"))
{
unused_syms[unused++] = &symtab.base[index];
symtab.base[index].has_been_placed = 1;
}
}
else
{
used_syms[used++] = &symtab.base[index];
symtab.base[index].has_been_placed = 0;
symtab.base[index].next = 0;
symtab.base[index].prev = 0;
symtab.base[index].nuses = 0;
}
}
/* Sort the arcs from most used to least used. */
qsort (arcs, numarcs, sizeof (Arc *), cmp_arc_count);
/* Compute the total arc count. Also mark arcs as unplaced.
Note we don't compensate for overflow if that happens!
Overflow is much less likely when this file is compiled
with GCC as it can double-wide integers via long long. */
total_arcs = 0;
for (index = 0; index < numarcs; index++)
{
total_arcs += arcs[index]->count;
arcs[index]->has_been_placed = 0;
}
/* We want to pull out those functions which are referenced
by many highly used arcs and emit them as a group. This
could probably use some tuning. */
tmp_arcs_count = 0;
for (index = 0; index < numarcs; index++)
{
tmp_arcs_count += arcs[index]->count;
/* Count how many times each parent and child are used up
to our threshhold of arcs (90%). */
if ((double)tmp_arcs_count / (double)total_arcs > 0.90)
break;
arcs[index]->child->nuses++;
}
/* Now sort a temporary symbol table based on the number of
times each function was used in the highest used arcs. */
bcopy (used_syms, scratch_syms, used * sizeof (Sym *));
qsort (scratch_syms, used, sizeof (Sym *), cmp_fun_nuses);
/* Now pick out those symbols we're going to emit as
a group. We take up to 1.25% of the used symbols. */
for (index = 0; index < used / 80; index++)
{
Sym *sym = scratch_syms[index];
Arc *arc;
/* If we hit symbols that aren't used from many call sites,
then we can quit. We choose five as the low limit for
no particular reason. */
if (sym->nuses == 5)
break;
/* We're going to need the arcs between these functions.
Unfortunately, we don't know all these functions
until we're done. So we keep track of all the arcs
to the functions we care about, then prune out those
which are uninteresting.
An interesting variation would be to quit when we found
multi-call site functions which account for some percentage
of the arcs. */
arc = sym->cg.children;
while (arc)
{
if (arc->parent != arc->child)
scratch_arcs[scratch_arc_count++] = arc;
arc->has_been_placed = 1;
arc = arc->next_child;
}
arc = sym->cg.parents;
while (arc)
{
if (arc->parent != arc->child)
scratch_arcs[scratch_arc_count++] = arc;
arc->has_been_placed = 1;
arc = arc->next_parent;
}
/* Keep track of how many symbols we're going to place. */
scratch_index = index;
/* A lie, but it makes identifying these functions easier
later. */
sym->has_been_placed = 1;
}
/* Now walk through the temporary arcs and copy those we care about
into the high arcs array. */
for (index = 0; index < scratch_arc_count; index++)
{
Arc *arc = scratch_arcs[index];
/* If this arc refers to highly used functions, then
then we want to keep it. */
if (arc->child->has_been_placed
&& arc->parent->has_been_placed)
{
high_arcs[high_arc_count++] = scratch_arcs[index];
/* We need to turn of has_been_placed since we're going to
use the main arc placement algorithm on these arcs. */
arc->child->has_been_placed = 0;
arc->parent->has_been_placed = 0;
}
}
/* Dump the multi-site high usage functions which are not going
to be ordered by the main ordering algorithm. */
for (index = 0; index < scratch_index; index++)
{
if (scratch_syms[index]->has_been_placed)
printf ("%s\n", scratch_syms[index]->name);
}
/* Now we can order the multi-site high use functions based on the
arcs between them. */
qsort (high_arcs, high_arc_count, sizeof (Arc *), cmp_arc_count);
order_and_dump_functions_by_arcs (high_arcs, high_arc_count, 1,
unplaced_arcs, &unplaced_arc_count);
/* Order and dump the high use functions left, these typically
have only a few call sites. */
order_and_dump_functions_by_arcs (arcs, numarcs, 0,
unplaced_arcs, &unplaced_arc_count);
/* Now place the rarely used functions. */
order_and_dump_functions_by_arcs (unplaced_arcs, unplaced_arc_count, 1,
scratch_arcs, &scratch_arc_count);
/* Output any functions not emitted by the order_and_dump calls. */
for (index = 0; index < used; index++)
if (used_syms[index]->has_been_placed == 0)
printf("%s\n", used_syms[index]->name);
/* Output the unused functions. */
for (index = 0; index < unused; index++)
printf("%s\n", unused_syms[index]->name);
unused_syms = (Sym **) xmalloc (symtab.len * sizeof (Sym *));
used_syms = (Sym **) xmalloc (symtab.len * sizeof (Sym *));
scratch_syms = (Sym **) xmalloc (symtab.len * sizeof (Sym *));
high_arcs = (Arc **) xmalloc (numarcs * sizeof (Arc *));
scratch_arcs = (Arc **) xmalloc (numarcs * sizeof (Arc *));
unplaced_arcs = (Arc **) xmalloc (numarcs * sizeof (Arc *));
free (unused_syms);
free (used_syms);
free (scratch_syms);
free (high_arcs);
free (scratch_arcs);
free (unplaced_arcs);
}
/* Place functions based on the arcs in ARCS with NUMARCS entries;
place unused arcs into UNPLACED_ARCS/UNPLACED_ARC_COUNT.
If ALL is nonzero, then place all functions referenced by ARCS,
else only place those referenced in the top 99% of the arcs in ARCS. */
#define MOST 0.99
static void
order_and_dump_functions_by_arcs (arcs, numarcs, all,
unplaced_arcs, unplaced_arc_count)
Arc **arcs;
unsigned long numarcs;
int all;
Arc **unplaced_arcs;
unsigned long *unplaced_arc_count;
{
#ifdef __GNU_C__
unsigned long long tmp_arcs, total_arcs;
#else
unsigned long tmp_arcs, total_arcs;
#endif
unsigned int index;
/* If needed, compute the total arc count.
Note we don't compensate for overflow if that happens! */
if (! all)
{
total_arcs = 0;
for (index = 0; index < numarcs; index++)
total_arcs += arcs[index]->count;
}
else
total_arcs = 0;
tmp_arcs = 0;
for (index = 0; index < numarcs; index++)
{
Sym *sym1, *sym2;
Sym *child, *parent;
tmp_arcs += arcs[index]->count;
/* Ignore this arc if it's already been placed. */
if (arcs[index]->has_been_placed)
continue;
child = arcs[index]->child;
parent = arcs[index]->parent;
/* If we're not using all arcs, and this is a rarely used
arc, then put it on the unplaced_arc list. Similarly
if both the parent and child of this arc have been placed. */
if ((! all && (double)tmp_arcs / (double)total_arcs > MOST)
|| child->has_been_placed || parent->has_been_placed)
{
unplaced_arcs[(*unplaced_arc_count)++] = arcs[index];
continue;
}
/* If all slots in the parent and child are full, then there isn't
anything we can do right now. We'll place this arc on the
unplaced arc list in the hope that a global positioning
algorithm can use it to place function chains. */
if (parent->next && parent->prev && child->next && child->prev)
{
unplaced_arcs[(*unplaced_arc_count)++] = arcs[index];
continue;
}
/* If the parent is unattached, then find the closest
place to attach it onto child's chain. Similarly
for the opposite case. */
if (!parent->next && !parent->prev)
{
int next_count = 0;
int prev_count = 0;
Sym *prev = child;
Sym *next = child;
/* Walk to the beginning and end of the child's chain. */
while (next->next)
{
next = next->next;
next_count++;
}
while (prev->prev)
{
prev = prev->prev;
prev_count++;
}
/* Choose the closest. */
child = next_count < prev_count ? next : prev;
}
else if (! child->next && !child->prev)
{
int next_count = 0;
int prev_count = 0;
Sym *prev = parent;
Sym *next = parent;
while (next->next)
{
next = next->next;
next_count++;
}
while (prev->prev)
{
prev = prev->prev;
prev_count++;
}
parent = prev_count < next_count ? prev : next;
}
else
{
/* Couldn't find anywhere to attach the functions,
put the arc on the unplaced arc list. */
unplaced_arcs[(*unplaced_arc_count)++] = arcs[index];
continue;
}
/* Make sure we don't tie two ends together. */
sym1 = parent;
if (sym1->next)
while (sym1->next)
sym1 = sym1->next;
else
while (sym1->prev)
sym1 = sym1->prev;
sym2 = child;
if (sym2->next)
while (sym2->next)
sym2 = sym2->next;
else
while (sym2->prev)
sym2 = sym2->prev;
if (sym1 == child
&& sym2 == parent)
{
/* This would tie two ends together. */
unplaced_arcs[(*unplaced_arc_count)++] = arcs[index];
continue;
}
if (parent->next)
{
/* Must attach to the parent's prev field. */
if (! child->next)
{
/* parent-prev and child-next */
parent->prev = child;
child->next = parent;
arcs[index]->has_been_placed = 1;
}
}
else if (parent->prev)
{
/* Must attach to the parent's next field. */
if (! child->prev)
{
/* parent-next and child-prev */
parent->next = child;
child->prev = parent;
arcs[index]->has_been_placed = 1;
}
}
else
{
/* Can attach to either field in the parent, depends
on where we've got space in the child. */
if (child->prev)
{
/* parent-prev and child-next */
parent->prev = child;
child->next = parent;
arcs[index]->has_been_placed = 1;
}
else
{
/* parent-next and child-prev */
parent->next = child;
child->prev = parent;
arcs[index]->has_been_placed = 1;
}
}
}
/* Dump the chains of functions we've made. */
for (index = 0; index < numarcs; index++)
{
Sym *sym;
if (arcs[index]->parent->has_been_placed
|| arcs[index]->child->has_been_placed)
continue;
sym = arcs[index]->parent;
/* If this symbol isn't attached to any other
symbols, then we've got a rarely used arc.
Skip it for now, we'll deal with them later. */
if (sym->next == NULL
&& sym->prev == NULL)
continue;
/* Get to the start of this chain. */
while (sym->prev)
sym = sym->prev;
while (sym)
{
/* Mark it as placed. */
sym->has_been_placed = 1;
printf ("%s\n", sym->name);
sym = sym->next;
}
}
/* If we want to place all the arcs, then output those which weren't
placed by the main algorithm. */
if (all)
for (index = 0; index < numarcs; index++)
{
Sym *sym;
if (arcs[index]->parent->has_been_placed
|| arcs[index]->child->has_been_placed)
continue;
sym = arcs[index]->parent;
sym->has_been_placed = 1;
printf ("%s\n", sym->name);
}
}
/* Print a suggested .o ordering for files on a link line based
on profiling information. This uses the function placement
code for the bulk of its work. */
struct function_map {
char *function_name;
char *file_name;
};
void
DEFUN_VOID (cg_print_file_ordering)
{
unsigned long scratch_arc_count, index;
Arc **scratch_arcs;
extern struct function_map *symbol_map;
extern int symbol_map_count;
char *last;
scratch_arc_count = 0;
scratch_arcs = (Arc **) xmalloc (numarcs * sizeof (Arc *));
for (index = 0; index < numarcs; index++)
{
if (! arcs[index]->parent->mapped
|| ! arcs[index]->child->mapped)
arcs[index]->has_been_placed = 1;
}
order_and_dump_functions_by_arcs (arcs, numarcs, 0,
scratch_arcs, &scratch_arc_count);
/* Output .o's not handled by the main placement algorithm. */
for (index = 0; index < symtab.len; index++)
{
if (symtab.base[index].mapped
&& ! symtab.base[index].has_been_placed)
printf ("%s\n", symtab.base[index].name);
}
/* Now output any .o's that didn't have any text symbols. */
last = NULL;
for (index = 0; index < symbol_map_count; index++)
{
int index2;
/* Don't bother searching if this symbol is the
same as the previous one. */
if (last && !strcmp (last, symbol_map[index].file_name))
continue;
for (index2 = 0; index2 < symtab.len; index2++)
{
if (! symtab.base[index2].mapped)
continue;
if (!strcmp (symtab.base[index2].name, symbol_map[index].file_name))
break;
}
/* If we didn't find it in the symbol table, then it must be a .o
with no text symbols. Output it last. */
if (index2 == symtab.len)
printf ("%s\n", symbol_map[index].file_name);
last = symbol_map[index].file_name;
}
}