commit 7827c40c49d841daca2a40463b8a60f9a113f77e
parent e7af9cdf0b9fca080e8bb3463e16d60933e786f9
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 10 Jan 2024 14:45:31 -0300
A few more tweaks in the garbage collector
Diffstat:
5 files changed, 33 insertions(+), 14 deletions(-)
diff --git a/config.lua b/config.lua
@@ -0,0 +1,4 @@
+collectgarbage("setparam", "minormul", 25)
+-- collectgarbage("generational")
+
+
diff --git a/lapi.c b/lapi.c
@@ -53,6 +53,16 @@ const char lua_ident[] =
#define isupvalue(i) ((i) < LUA_REGISTRYINDEX)
+/* Advance the garbage collector when creating large objects */
+static void advancegc (lua_State *L, size_t delta) {
+ delta >>= 5; /* one object for each 32 bytes (empirical) */
+ if (delta > 0) {
+ global_State *g = G(L);
+ luaE_setdebt(g, g->GCdebt - delta);
+ }
+}
+
+
/*
** Convert an acceptable index to a pointer to its respective value.
** Non-valid indices return the special nil value 'G(L)->nilvalue'.
@@ -530,6 +540,7 @@ LUA_API const char *lua_pushlstring (lua_State *L, const char *s, size_t len) {
ts = (len == 0) ? luaS_new(L, "") : luaS_newlstr(L, s, len);
setsvalue2s(L, L->top.p, ts);
api_incr_top(L);
+ advancegc(L, len);
luaC_checkGC(L);
lua_unlock(L);
return getstr(ts);
@@ -544,6 +555,8 @@ LUA_API const char *lua_pushextlstring (lua_State *L,
ts = luaS_newextlstr (L, s, len, falloc, ud);
setsvalue2s(L, L->top.p, ts);
api_incr_top(L);
+ if (falloc != NULL) /* non-static string? */
+ advancegc(L, len); /* count its memory */
luaC_checkGC(L);
lua_unlock(L);
return getstr(ts);
@@ -1336,6 +1349,7 @@ LUA_API void *lua_newuserdatauv (lua_State *L, size_t size, int nuvalue) {
u = luaS_newudata(L, size, nuvalue);
setuvalue(L, s2v(L->top.p), u);
api_incr_top(L);
+ advancegc(L, size);
luaC_checkGC(L);
lua_unlock(L);
return getudatamem(u);
diff --git a/lgc.c b/lgc.c
@@ -1052,6 +1052,7 @@ static void setpause (global_State *g) {
l_obj threshold = applygcparam(g, PAUSE, g->marked);
l_obj debt = threshold - gettotalobjs(g);
if (debt < 0) debt = 0;
+//printf("pause: %ld %ld\n", debt, g->marked);
luaE_setdebt(g, debt);
}
@@ -1246,7 +1247,7 @@ static void minor2inc (lua_State *L, global_State *g, int kind) {
/*
** Decide whether to shift to major mode. It tests two conditions:
** 1) Whether the number of added old objects in this collection is more
-** than half the number of new objects. ("step" is the number of objects
+** than half the number of new objects. ('step' is the number of objects
** created between minor collections. Except for forward barriers, it
** is the maximum number of objects that can become old in each minor
** collection.)
@@ -1254,15 +1255,11 @@ static void minor2inc (lua_State *L, global_State *g, int kind) {
** than 'minormajor'% of the number of lived objects after the last
** major collection. (That percentage is computed in 'limit'.)
*/
-static int checkminormajor (lua_State *L, global_State *g, l_obj addedold1) {
+static int checkminormajor (global_State *g, l_obj addedold1) {
l_obj step = applygcparam(g, MINORMUL, g->GCmajorminor);
l_obj limit = applygcparam(g, MINORMAJOR, g->GCmajorminor);
-//printf("-> major? %ld %ld %ld %ld (%ld)\n", g->marked, limit, step, addedold1, gettotalobjs(g));
- if (addedold1 >= (step >> 1) || g->marked >= limit) {
- minor2inc(L, g, KGC_GENMAJOR); /* go to major mode */
- return 1;
- }
- return 0; /* stay in minor mode */
+//printf("-> (%ld) major? marked: %ld limit: %ld step: %ld addedold1: %ld)\n", gettotalobjs(g), g->marked, limit, step, addedold1);
+ return (addedold1 >= (step >> 1) || g->marked >= limit);
}
/*
@@ -1309,7 +1306,11 @@ static void youngcollection (lua_State *L, global_State *g) {
g->marked = marked + addedold1;
/* decide whether to shift to major mode */
- if (!checkminormajor(L, g, addedold1))
+ if (checkminormajor(g, addedold1)) {
+ minor2inc(L, g, KGC_GENMAJOR); /* go to major mode */
+ g->marked = 0; /* avoid pause in first major cycle */
+ }
+ else
finishgencycle(L, g); /* still in minor mode; finish it */
}
@@ -1401,12 +1402,12 @@ static void fullgen (lua_State *L, global_State *g) {
** since the last collection ('addedobjs').
*/
static int checkmajorminor (lua_State *L, global_State *g) {
- if (g->gckind == KGC_GENMAJOR) {
+ if (g->gckind == KGC_GENMAJOR) { /* generational mode? */
l_obj numobjs = gettotalobjs(g);
l_obj addedobjs = numobjs - g->GCmajorminor;
l_obj limit = applygcparam(g, MAJORMINOR, addedobjs);
l_obj tobecollected = numobjs - g->marked;
-//printf("-> minor? %ld %ld %ld\n", tobecollected, limit, numobjs);
+//printf("(%ld) -> minor? tobecollected: %ld limit: %ld\n", numobjs, tobecollected, limit);
if (tobecollected > limit) {
atomic2gen(L, g); /* return to generational mode */
setminordebt(g);
diff --git a/lgc.h b/lgc.h
@@ -183,7 +183,7 @@
/* incremental */
/* Number of objects must be LUAI_GCPAUSE% before starting new cycle */
-#define LUAI_GCPAUSE 300
+#define LUAI_GCPAUSE 200
/* Step multiplier. (Roughly, the collector handles LUAI_GCMUL% objects
for each new allocated object.) */
diff --git a/manual/manual.of b/manual/manual.of
@@ -664,7 +664,7 @@ Values equal to or less than 100 mean the collector will not wait to
start a new cycle.
A value of 200 means that the collector waits for
the total number of objects to double before starting a new cycle.
-The default value is 300; the maximum value is 1000.
+The default value is 200.
The garbage-collector step size controls the
size of each incremental step,
@@ -681,7 +681,7 @@ in each step, @M{n%} objects for each created object.
Larger values make the collector more aggressive.
Beware that values too small can
make the collector too slow to ever finish a cycle.
-The default value is 200; the maximum value is 1000.
+The default value is 200.
As a special case, a zero value means unlimited work,
effectively producing a non-incremental, stop-the-world collector.
