Changeset 147c9f6 in mainline

Timestamp:

2011-03-31T17:10:23Z (14 years ago)

Author:

Maurizio Lombardi <m.lombardi85@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

bd64680

Parents:

b438804

Message:

Performace optimization:

Use zsearch and isearch to store the index of the first free bit of the bitmap, not of the first block
where the free bit is found.

File:

• uspace/srv/fs/minixfs/mfs_balloc.c (modified) (9 diffs)

uspace/srv/fs/minixfs/mfs_balloc.c

@@ -6 +6 @@
 
 static int
-find_free_bit_and_set(bitchunk_t *b, const int bsize, const bool native);
+find_free_bit_and_set(bitchunk_t *b, const int bsize,
+                                const bool native, unsigned start_bit);
 
 int
@@ -67 +68 @@
         unsigned long nblocks;
         unsigned *search, i, start_block;
+        unsigned bits_per_block;
         int r, freebit;
 
@@ -85 +87 @@
                 limit = sbi->ninodes;
         }
+        bits_per_block = sbi->block_size * 8;
 
         block_t *b;
@@ -90 +93 @@
 retry:
 
-        for (i = *search; i < nblocks; ++i) {
+        for (i = *search / bits_per_block; i < nblocks; ++i) {
                 r = block_get(&b, inst->handle, i, BLOCK_FLAGS_NONE);
 
@@ -97 +100 @@
 
                 freebit = find_free_bit_and_set(b->data, sbi->block_size,
-                                                sbi->native);
+                                                sbi->native, *search);
                 if (freebit == -1) {
                         /*No free bit in this block*/
@@ -112 +115 @@
                 }
 
-                *search = i;
+                *search = i * bits_per_block + *idx;
                 b->dirty = true;
                 block_put(b);
@@ -135 +138 @@
 
 static int
-find_free_bit_and_set(bitchunk_t *b, const int bsize, const bool native)
+find_free_bit_and_set(bitchunk_t *b, const int bsize,
+                                const bool native, unsigned start_bit)
 {
         int r = -1;
@@ -141 +145 @@
         bitchunk_t chunk;
 
-        for (i = 0; i < bsize / sizeof(uint32_t); ++i, ++b) {
-                if (~*b) {
+        for (i = start_bit; i < bsize / sizeof(uint32_t); ++i) {
+                if (~b[i]) {
                         /*No free bit in this chunk*/
                         continue;
                 }
 
-                chunk = conv32(native, *b);
+                chunk = conv32(native, b[i]);
 
                 for (j = 0; j < 32; ++j) {
@@ -153 +157 @@
                                 r = i * 32 + j;
                                 chunk |= 1 << j;
-                                *b = conv32(native, chunk);
+                                b[i] = conv32(native, chunk);
                                 goto found;
                         }