Most of the memory used by Polipo is stored in chunks, fixed-size
blocks of memory; the size of a chunk is defined by the compile-time
CHUNK_SIZE, and defaults to 4096 bytes on 32-bit
platforms, 8192 on 64-bit ones. Chunks are used for storing object
data (bodies of instances) and for temporary I/O buffers. Increasing
the chunk size increases performance somewhat, but at the cost of
larger granularity of allocation and hence larger memory usage.
By default, Polipo uses a hand-crafted memory allocator based on
VirtualAlloc under Windows) for allocating
chunks; while this is very slightly faster than the stock memory
allocator, its main benefit is that it limits memory fragmentation.
It is possible to disable the chunk allocator, and use
malloc(3) for all memory allocation, by defining
MALLOC_CHUNKS at compile time; this is probably only useful for
There is one assumption made about
CHUNK_SIZE multiplied by the number of bits in an
unsigned long (actually in a
ChunkBitmap — see
chunk.c) must be a multiple of the page size, which is 4096 on
most systems (8192 on Alpha, and apparently 65536 on Windows).
As all network I/O will be performed in units of one to two chunks,
CHUNK_SIZE should be at least equal to your network interface’s
MTU (typically 1500 bytes). Additionally, as much I/O will be done at
CHUNK_SIZE should ideally
be a multiple of the page size.
In summary, 2048, 4096, 8192 and 16384 are good choices for