AuroraMiddleware/gtk2
1
0
Fork 0
forked from AuroraMiddleware/gtk
Code Issues Pull Requests Projects Releases Wiki Activity

timsort: Make sure merges don't take too long

Browse Source 
Limit the size of the merged areas and thereby chunk larger merges into
smaller ones.
This commit is contained in:
Benjamin Otte 2020-07-11 20:34:16 +02:00
parent 47232acbd8
commit 8921dadaa1
2 changed files with 53 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
gtk/gtktimsort-impl.c
View File

@ -805,18 +805,6 @@ gtk_tim_sort(merge_at) (GtkTimSort *self,
g_assert (len1 > 0 && len2 > 0);
g_assert (ELEM (base1, len1) == base2);
/*
* Record the length of the combined runs; if i is the 3rd-last
* run now, also slide over the last run (which isn't involved
* in this merge). The current run (i+1) goes away in any case.
*/
self->run[i].len = len1 + len2;
if (i == self->pending_runs - 3)
{
self->run[i + 1] = self->run[i + 2];
}
self->pending_runs--;
/*
* Find where the first element of run2 goes in run1. Prior elements
* in run1 can be ignored (because they're already in place).
@ -825,7 +813,7 @@ gtk_tim_sort(merge_at) (GtkTimSort *self,
base1 = ELEM (base1, k);
len1 -= k;
if (len1 == 0)
return;
goto done;
/*
* Find where the last element of run1 goes in run2. Subsequent elements
@ -835,13 +823,53 @@ gtk_tim_sort(merge_at) (GtkTimSort *self,
ELEM (base1, len1 - 1),
base2, len2, len2 - 1);
if (len2 == 0)
return;
goto done;
/* Merge remaining runs, using tmp array with min(len1, len2) elements */
if (len1 <= len2)
gtk_tim_sort(merge_lo) (self, base1, len1, base2, len2);
{
if (len1 > MAX_MERGE_PER_RUN)
{
base1 = ELEM (self->run[i].base, self->run[i].len - MAX_MERGE_PER_RUN);
gtk_tim_sort(merge_lo) (self, base1, MAX_MERGE_PER_RUN, base2, len2);
self->run[i].len -= MAX_MERGE_PER_RUN;
self->run[i + 1].base = ELEM (self->run[i + 1].base, - MAX_MERGE_PER_RUN);
self->run[i + 1].len += MAX_MERGE_PER_RUN;
g_assert (ELEM (self->run[i].base, self->run[i].len) == self->run[i + 1].base);
return;
}
else
{
gtk_tim_sort(merge_lo) (self, base1, len1, base2, len2);
}
}
else
gtk_tim_sort(merge_hi) (self, base1, len1, base2, len2);
{
if (len2 > MAX_MERGE_PER_RUN)
{
gtk_tim_sort(merge_hi) (self, base1, len1, base2, MAX_MERGE_PER_RUN);
self->run[i].len += MAX_MERGE_PER_RUN;
self->run[i + 1].base = ELEM (self->run[i + 1].base, MAX_MERGE_PER_RUN);
self->run[i + 1].len -= MAX_MERGE_PER_RUN;
g_assert (ELEM (self->run[i].base, self->run[i].len) == self->run[i + 1].base);
return;
}
else
{
gtk_tim_sort(merge_hi) (self, base1, len1, base2, len2);
}
}
done:
/*
* Record the length of the combined runs; if i is the 3rd-last
* run now, also slide over the last run (which isn't involved
* in this merge). The current run (i+1) goes away in any case.
*/
self->run[i].len += self->run[i + 1].len;
if (i == self->pending_runs - 3)
self->run[i + 1] = self->run[i + 2];
self->pending_runs--;
}

9
gtk/gtktimsort.c
View File

@ -25,6 +25,15 @@
*/
#define MIN_MERGE 32
/*
* Limit the amount of work done when merging. This ensures that the step
* function does not take too much time. Of coure, there's overhead associated
* with splitting a merge into miultliple merges.
*
* So lowering this number will make the average runtime of the step function
* faster but increase the total runtime.
*/
#define MAX_MERGE_PER_RUN 1024
/*
* When we get into galloping mode, we stay there until both runs win less