RE: Reducing memory consumption
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- Subject: RE: Reducing memory consumption
- From: "Jasmin Patry" <jpatry@...>
- Date: 2004年8月27日 12:11:29 -0700
I'm looking at this right now myself.
I've found a few minor optimizations in the Lua core itself (based on
5.1work). These aren't necessarily general-purpose, but they are
applicable for us (running on the PS2):
I changed the definition of Proto to this. This reduced the size of
Proto from 72 bytes to 56 bytes. This required a few changes elsewhere,
but they are pretty straightforward.
typedef struct Proto {
CommonHeader;
TValue *k; /* constants used by the function */
Instruction *code;
struct Proto **p; /* functions defined inside the function */
lu_short *lineinfo; /* map from opcodes to source lines */ /* CHANGE
*/
struct LocVar *locvars; /* information about local variables */
TString **upvalues; /* upvalue names */
TString *source;
GCObject *gclist;
lu_short lineDefined; /* CHANGE */
lu_short sizecode; /* CHANGE */
lu_short sizelineinfo; /* CHANGE */
lu_short sizelocvars; /* CHANGE */
lu_short sizek; /* size of `k' */ /* CHANGE */
lu_byte sizeupvalues; /* CHANGE */
lu_byte sizep; /* size of `p' */ /* CHANGE */
lu_byte nups; /* number of upvalues */
lu_byte numparams;
lu_byte is_vararg;
lu_byte maxstacksize;
} Proto;
Note that this could be reduced further in release builds by removing
the entries that are stripped when debug info isn't included.
I was also able to reduce the size of Table by 4 bytes:
typedef struct Table {
CommonHeader;
lu_byte flags; /* 1<<p means tagmethod(p) is not present */
lu_byte lsizenode; /* log2 of size of `node' array */
struct Table *metatable;
TValue *array; /* array part */
Node *node;
GCObject *gclist;
lu_short sizearray; /* size of `array' array */ /* CHANGE */
lu_short firstfreeidx; /* this position is free; all positions after
it are full */ /* CHANGE */
} Table;
This limits arrays to having a maximum size of 2^16, but that's fine for
our purposes. This reduces the size of Table from 32 bytes to 28 bytes;
not huge but still worthwhile.
Cheers,
Jasmin
-----Original Message-----
From: Nick Trout [mailto:nick@rockstarvancouver.com]
Sent: Friday, August 27, 2004 11:49 AM
To: Lua list
Subject: Reducing memory consumption
So, this is quite an opened question and I have few ideas but I'd like
to throw it out open... What ideas do people have for reducing the
memory consumption of Lua in working scripts?
Nick