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Moved redundant blocks into the lfsr_rbyd_t struct

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This simplifies dependent structs with redundancy, mainly lfsr_mdir_t,
at a significant RAM cost:

            code          stack          structs
  before:  30976           2496             1072
  after:   30948 (-0.1%)   2528 (+1.3%)     1100 (+2.6%)

Which, to be honest, is not as bad as I thought it would be. Though it
is still pretty bad for no new features.

The motivation for this change:

1. The organization of the previous lfsr_mdir_t struct was a bit hacky
   and relied on exact padding so the redund block array and rbyd block
   lined up at the right offset.

2. The previous organization prevented theoretical "read-only rbyd
   structs" that could omit write-related fields, e.g. eoff and cksum.

   This idea is currently unused.

3. The current mdir=level-1, btree/data=level-0 redund design makes this
   RAM tradeoff pretty bad, but in theory higher btree redund levels
   would need the extra redund blocks in the rbyd struct anyways.

Still, the RAM impact to the current default configuration means this
should probably be reverted...
This commit is contained in:
Christopher Haster
2023-11-26 00:19:08 -06:00
parent 019044e4c6
commit becbc0c2ad
6 changed files with 1171 additions and 1169 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tests/test_alloc.toml
+27 -24
View File
@@ -176,22 +176,23 @@ code = '''
if (tinfo.tag == LFSR_TAG_MDIR) {
printf("traversal: 0x%x mdir 0x{%x,%x}\n",
tinfo.tag,
tinfo.u.mdir.u.mdir.blocks[0],
tinfo.u.mdir.u.mdir.blocks[1]);
tinfo.u.mdir.rbyd.blocks[0],
tinfo.u.mdir.rbyd.blocks[1]);
// keep track of seen blocks
seen[tinfo.u.mdir.u.mdir.blocks[1] / 8]
|= 1 << (tinfo.u.mdir.u.mdir.blocks[1] % 8);
seen[tinfo.u.mdir.u.mdir.blocks[0] / 8]
|= 1 << (tinfo.u.mdir.u.mdir.blocks[0] % 8);
seen[tinfo.u.mdir.rbyd.blocks[1] / 8]
|= 1 << (tinfo.u.mdir.rbyd.blocks[1] % 8);
seen[tinfo.u.mdir.rbyd.blocks[0] / 8]
|= 1 << (tinfo.u.mdir.rbyd.blocks[0] % 8);
} else if (tinfo.tag == LFSR_TAG_BRANCH) {
printf("traversal: 0x%x btree 0x%x.%x\n",
tinfo.tag,
tinfo.u.rbyd.block, tinfo.u.rbyd.trunk);
tinfo.u.rbyd.blocks[0], tinfo.u.rbyd.trunk);
// keep track of seen blocks
seen[tinfo.u.rbyd.block / 8] |= 1 << (tinfo.u.rbyd.block % 8);
seen[tinfo.u.rbyd.blocks[0] / 8]
|= 1 << (tinfo.u.rbyd.blocks[0] % 8);
} else {
// this shouldn't happen
@@ -332,22 +333,23 @@ code = '''
if (tinfo.tag == LFSR_TAG_MDIR) {
printf("traversal: 0x%x mdir 0x{%x,%x}\n",
tinfo.tag,
tinfo.u.mdir.u.mdir.blocks[0],
tinfo.u.mdir.u.mdir.blocks[1]);
tinfo.u.mdir.rbyd.blocks[0],
tinfo.u.mdir.rbyd.blocks[1]);
// keep track of seen blocks
seen[tinfo.u.mdir.u.mdir.blocks[1] / 8]
|= 1 << (tinfo.u.mdir.u.mdir.blocks[1] % 8);
seen[tinfo.u.mdir.u.mdir.blocks[0] / 8]
|= 1 << (tinfo.u.mdir.u.mdir.blocks[0] % 8);
seen[tinfo.u.mdir.rbyd.blocks[1] / 8]
|= 1 << (tinfo.u.mdir.rbyd.blocks[1] % 8);
seen[tinfo.u.mdir.rbyd.blocks[0] / 8]
|= 1 << (tinfo.u.mdir.rbyd.blocks[0] % 8);
} else if (tinfo.tag == LFSR_TAG_BRANCH) {
printf("traversal: 0x%x btree 0x%x.%x\n",
tinfo.tag,
tinfo.u.rbyd.block, tinfo.u.rbyd.trunk);
tinfo.u.rbyd.blocks[0], tinfo.u.rbyd.trunk);
// keep track of seen blocks
seen[tinfo.u.rbyd.block / 8] |= 1 << (tinfo.u.rbyd.block % 8);
seen[tinfo.u.rbyd.blocks[0] / 8]
|= 1 << (tinfo.u.rbyd.blocks[0] % 8);
} else if (tinfo.tag == LFSR_TAG_BLOCK) {
printf("traversal: 0x%x block 0x%x\n",
@@ -478,22 +480,23 @@ code = '''
if (tinfo.tag == LFSR_TAG_MDIR) {
printf("traversal: 0x%x mdir 0x{%x,%x}\n",
tinfo.tag,
tinfo.u.mdir.u.mdir.blocks[0],
tinfo.u.mdir.u.mdir.blocks[1]);
tinfo.u.mdir.rbyd.blocks[0],
tinfo.u.mdir.rbyd.blocks[1]);
// keep track of seen blocks
seen[tinfo.u.mdir.u.mdir.blocks[1] / 8]
|= 1 << (tinfo.u.mdir.u.mdir.blocks[1] % 8);
seen[tinfo.u.mdir.u.mdir.blocks[0] / 8]
|= 1 << (tinfo.u.mdir.u.mdir.blocks[0] % 8);
seen[tinfo.u.mdir.rbyd.blocks[1] / 8]
|= 1 << (tinfo.u.mdir.rbyd.blocks[1] % 8);
seen[tinfo.u.mdir.rbyd.blocks[0] / 8]
|= 1 << (tinfo.u.mdir.rbyd.blocks[0] % 8);
} else if (tinfo.tag == LFSR_TAG_BRANCH) {
printf("traversal: 0x%x btree 0x%x.%x\n",
tinfo.tag,
tinfo.u.rbyd.block, tinfo.u.rbyd.trunk);
tinfo.u.rbyd.blocks[0], tinfo.u.rbyd.trunk);
// keep track of seen blocks
seen[tinfo.u.rbyd.block / 8] |= 1 << (tinfo.u.rbyd.block % 8);
seen[tinfo.u.rbyd.blocks[0] / 8]
|= 1 << (tinfo.u.rbyd.blocks[0] % 8);
} else if (tinfo.tag == LFSR_TAG_BLOCK) {
printf("traversal: 0x%x block 0x%x\n",