* [RFC PATCH v0 1/3] erofs-utils: add -C# for the maximum size of pclusters
2020-12-30 8:47 ` [RFC PATCH v0 0/3] erofs-utils: support multiple block compression Gao Xiang via Linux-erofs
@ 2020-12-30 8:47 ` Gao Xiang via Linux-erofs
2020-12-30 8:47 ` [RFC PATCH v0 2/3] erofs-utils: mkfs: support multiple block compression Gao Xiang via Linux-erofs
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Gao Xiang via Linux-erofs @ 2020-12-30 8:47 UTC (permalink / raw)
To: linux-erofs
From: Gao Xiang <hsiangkao@aol.com>
Set up -C >= EROFS_BLKSIZ (more specifically, >= lclustersize)
to enable big pcluster feature.
Signed-off-by: Gao Xiang <hsiangkao@aol.com>
---
include/erofs/config.h | 2 ++
lib/config.c | 1 +
mkfs/main.c | 14 +++++++++++++-
3 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/include/erofs/config.h b/include/erofs/config.h
index 02ddf594ca60..5f5a05a8b796 100644
--- a/include/erofs/config.h
+++ b/include/erofs/config.h
@@ -53,6 +53,8 @@ struct erofs_configure {
int c_force_inodeversion;
/* < 0, xattr disabled and INT_MAX, always use inline xattrs */
int c_inline_xattr_tolerance;
+
+ u32 c_physical_clusterblks;
u64 c_unix_timestamp;
#ifdef WITH_ANDROID
char *mount_point;
diff --git a/lib/config.c b/lib/config.c
index 3ecd48140cfd..352a77c8d639 100644
--- a/lib/config.c
+++ b/lib/config.c
@@ -24,6 +24,7 @@ void erofs_init_configure(void)
cfg.c_force_inodeversion = 0;
cfg.c_inline_xattr_tolerance = 2;
cfg.c_unix_timestamp = -1;
+ cfg.c_physical_clusterblks = 1;
}
void erofs_show_config(void)
diff --git a/mkfs/main.c b/mkfs/main.c
index abd48be0fa4f..c4c67c962919 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -62,6 +62,7 @@ static void usage(void)
fputs("usage: [options] FILE DIRECTORY\n\n"
"Generate erofs image from DIRECTORY to FILE, and [options] are:\n"
" -zX[,Y] X=compressor (Y=compression level, optional)\n"
+ " -C# specify the size of compress physical cluster in bytes\n"
" -d# set output message level to # (maximum 9)\n"
" -x# set xattr tolerance to # (< 0, disable xattrs; default 2)\n"
" -EX[,...] X=extended options\n"
@@ -152,7 +153,7 @@ static int mkfs_parse_options_cfg(int argc, char *argv[])
char *endptr;
int opt, i;
- while((opt = getopt_long(argc, argv, "d:x:z:E:T:U:",
+ while((opt = getopt_long(argc, argv, "d:x:z:E:T:U:C:",
long_options, NULL)) != -1) {
switch (opt) {
case 'z':
@@ -248,6 +249,17 @@ static int mkfs_parse_options_cfg(int argc, char *argv[])
cfg.fs_config_file = optarg;
break;
#endif
+ case 'C':
+ i = strtoull(optarg, &endptr, 0);
+ if (*endptr != '\0' ||
+ i < EROFS_BLKSIZ || i % EROFS_BLKSIZ) {
+ erofs_err("invalid physical clustersize %s",
+ optarg);
+ return -EINVAL;
+ }
+ cfg.c_physical_clusterblks = i / EROFS_BLKSIZ;
+ break;
+
case 1:
usage();
exit(0);
--
2.24.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [RFC PATCH v0 2/3] erofs-utils: mkfs: support multiple block compression
2020-12-30 8:47 ` [RFC PATCH v0 0/3] erofs-utils: support multiple block compression Gao Xiang via Linux-erofs
2020-12-30 8:47 ` [RFC PATCH v0 1/3] erofs-utils: add -C# for the maximum size of pclusters Gao Xiang via Linux-erofs
@ 2020-12-30 8:47 ` Gao Xiang via Linux-erofs
2020-12-30 8:47 ` [RFC PATCH v0 3/3] erofs-utils: fuse: " Gao Xiang via Linux-erofs
2020-12-30 10:12 ` [RFC PATCH v0 0/3] erofs-utils: " Gao Xiang
3 siblings, 0 replies; 5+ messages in thread
From: Gao Xiang via Linux-erofs @ 2020-12-30 8:47 UTC (permalink / raw)
To: linux-erofs
From: Gao Xiang <hsiangkao@aol.com>
Store compressed block count to the compressed index so that EROFS
can compress from variable-sized input to variable-sized compressed
blocks and make the in-place decompression possible as well.
TODO: support storing compressed block count for compact indexes.
Signed-off-by: Gao Xiang <hsiangkao@aol.com>
---
include/erofs/internal.h | 1 +
include/erofs_fs.h | 19 ++++++++---
lib/compress.c | 70 ++++++++++++++++++++++++++--------------
3 files changed, 62 insertions(+), 28 deletions(-)
diff --git a/include/erofs/internal.h b/include/erofs/internal.h
index ac5b270329e2..de307e7f3d8f 100644
--- a/include/erofs/internal.h
+++ b/include/erofs/internal.h
@@ -104,6 +104,7 @@ static inline void erofs_sb_clear_##name(void) \
}
EROFS_FEATURE_FUNCS(lz4_0padding, incompat, INCOMPAT_LZ4_0PADDING)
+EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)
EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
#define EROFS_I_EA_INITED (1 << 0)
diff --git a/include/erofs_fs.h b/include/erofs_fs.h
index a69f179a51a5..fa9467a2608c 100644
--- a/include/erofs_fs.h
+++ b/include/erofs_fs.h
@@ -20,7 +20,10 @@
* be incompatible with this kernel version.
*/
#define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING 0x00000001
-#define EROFS_ALL_FEATURE_INCOMPAT EROFS_FEATURE_INCOMPAT_LZ4_0PADDING
+#define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER 0x00000002
+#define EROFS_ALL_FEATURE_INCOMPAT \
+ (EROFS_FEATURE_INCOMPAT_LZ4_0PADDING | \
+ EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER)
/* 128-byte erofs on-disk super block */
struct erofs_super_block {
@@ -201,10 +204,11 @@ enum {
* bit 0 : COMPACTED_2B indexes (0 - off; 1 - on)
* e.g. for 4k logical cluster size, 4B if compacted 2B is off;
* (4B) + 2B + (4B) if compacted 2B is on.
+ * bit 1 : HEAD1 big pcluster (0 - off; 1 - on)
+ * bit 2 : (reserved now) HEAD2 big pcluster (0 - off; 1 - on)
*/
-#define Z_EROFS_ADVISE_COMPACTED_2B_BIT 0
-
-#define Z_EROFS_ADVISE_COMPACTED_2B (1 << Z_EROFS_ADVISE_COMPACTED_2B_BIT)
+#define Z_EROFS_ADVISE_COMPACTED_2B 0x0001
+#define Z_EROFS_ADVISE_BIG_PCLUSTER_1 0x0002
struct z_erofs_map_header {
__le32 h_reserved1;
@@ -261,6 +265,13 @@ enum {
#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS 2
#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT 0
+/*
+ * D0_CBLKCNT will be marked _only_ for the 1st non-head lcluster to
+ * store the compressed block count of a compressed extent (aka. block
+ * count of a pcluster).
+ */
+#define Z_EROFS_VLE_DI_D0_CBLKCNT 0x8000
+
struct z_erofs_vle_decompressed_index {
__le16 di_advise;
/* where to decompress in the head cluster */
diff --git a/lib/compress.c b/lib/compress.c
index 86db940b6edd..f340f432c6b7 100644
--- a/lib/compress.c
+++ b/lib/compress.c
@@ -29,8 +29,8 @@ struct z_erofs_vle_compress_ctx {
u8 queue[EROFS_CONFIG_COMPR_MAX_SZ * 2];
unsigned int head, tail;
-
- erofs_blk_t blkaddr; /* pointing to the next blkaddr */
+ unsigned int compressedblks;
+ erofs_blk_t blkaddr; /* pointing to the next blkaddr */
u16 clusterofs;
};
@@ -89,7 +89,13 @@ static void vle_write_indexes(struct z_erofs_vle_compress_ctx *ctx,
}
do {
- if (d0) {
+ /* XXX: big pcluster feature should be per-inode */
+ if (d0 == 1 && cfg.c_physical_clusterblks > 1) {
+ type = Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD;
+ di.di_u.delta[0] = cpu_to_le16(ctx->compressedblks |
+ Z_EROFS_VLE_DI_D0_CBLKCNT);
+ di.di_u.delta[1] = cpu_to_le16(d1);
+ } else if (d0) {
type = Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD;
di.di_u.delta[0] = cpu_to_le16(d0);
@@ -115,9 +121,8 @@ static void vle_write_indexes(struct z_erofs_vle_compress_ctx *ctx,
ctx->clusterofs = clusterofs + count;
}
-static int write_uncompressed_block(struct z_erofs_vle_compress_ctx *ctx,
- unsigned int *len,
- char *dst)
+static int write_uncompressed_extent(struct z_erofs_vle_compress_ctx *ctx,
+ unsigned int *len, char *dst)
{
int ret;
unsigned int count;
@@ -148,17 +153,19 @@ static int vle_compress_one(struct erofs_inode *inode,
struct z_erofs_vle_compress_ctx *ctx,
bool final)
{
+ const unsigned int pclusterblks = cfg.c_physical_clusterblks;
+ const unsigned int pclustersize = pclusterblks * EROFS_BLKSIZ;
struct erofs_compress *const h = &compresshandle;
unsigned int len = ctx->tail - ctx->head;
unsigned int count;
int ret;
- static char dstbuf[EROFS_BLKSIZ * 2];
+ static char dstbuf[EROFS_CONFIG_COMPR_MAX_SZ + EROFS_BLKSIZ];
char *const dst = dstbuf + EROFS_BLKSIZ;
while (len) {
bool raw;
- if (len <= EROFS_BLKSIZ) {
+ if (len <= pclustersize) {
if (final)
goto nocompression;
break;
@@ -167,7 +174,7 @@ static int vle_compress_one(struct erofs_inode *inode,
count = len;
ret = erofs_compress_destsize(h, compressionlevel,
ctx->queue + ctx->head,
- &count, dst, EROFS_BLKSIZ);
+ &count, dst, pclustersize);
if (ret <= 0) {
if (ret != -EAGAIN) {
erofs_err("failed to compress %s: %s",
@@ -175,32 +182,36 @@ static int vle_compress_one(struct erofs_inode *inode,
erofs_strerror(ret));
}
nocompression:
- ret = write_uncompressed_block(ctx, &len, dst);
+ ret = write_uncompressed_extent(ctx, &len, dst);
if (ret < 0)
return ret;
count = ret;
+ ctx->compressedblks = 1;
raw = true;
} else {
- /* write compressed data */
- erofs_dbg("Writing %u compressed data to block %u",
- count, ctx->blkaddr);
+ const unsigned int used = ret & (EROFS_BLKSIZ - 1);
+ const unsigned int margin =
+ erofs_sb_has_lz4_0padding() && used ?
+ EROFS_BLKSIZ - used : 0;
- if (erofs_sb_has_lz4_0padding())
- ret = blk_write(dst - (EROFS_BLKSIZ - ret),
- ctx->blkaddr, 1);
- else
- ret = blk_write(dst, ctx->blkaddr, 1);
+ ctx->compressedblks = DIV_ROUND_UP(ret, EROFS_BLKSIZ);
+ /* write compressed data */
+ erofs_dbg("Writing %u compressed data to %u of %u blocks",
+ count, ctx->blkaddr, ctx->compressedblks);
+
+ ret = blk_write(dst - margin, ctx->blkaddr,
+ ctx->compressedblks);
if (ret)
return ret;
raw = false;
}
ctx->head += count;
- /* write compression indexes for this blkaddr */
+ /* write compression indexes for this pcluster */
vle_write_indexes(ctx, count, raw);
- ++ctx->blkaddr;
+ ctx->blkaddr += ctx->compressedblks;
len -= count;
if (!final && ctx->head >= EROFS_CONFIG_COMPR_MAX_SZ) {
@@ -345,8 +356,6 @@ int z_erofs_convert_to_compacted_format(struct erofs_inode *inode,
out = in = inode->compressmeta;
- /* write out compacted header */
- memcpy(out, &mapheader, sizeof(mapheader));
out += sizeof(mapheader);
in += Z_EROFS_LEGACY_MAP_HEADER_SIZE;
@@ -415,6 +424,8 @@ int erofs_write_compressed_file(struct erofs_inode *inode)
}
memset(compressmeta, 0, Z_EROFS_LEGACY_MAP_HEADER_SIZE);
+ /* write out compressed header */
+ memcpy(compressmeta, &mapheader, sizeof(mapheader));
blkaddr = erofs_mapbh(bh->block, true); /* start_blkaddr */
ctx.blkaddr = blkaddr;
@@ -473,7 +484,8 @@ int erofs_write_compressed_file(struct erofs_inode *inode)
inode->u.i_blocks = compressed_blocks;
legacymetasize = ctx.metacur - compressmeta;
- if (cfg.c_legacy_compress) {
+ /* XXX: temporarily use legacy index instead for mbpcluster */
+ if (cfg.c_legacy_compress || cfg.c_physical_clusterblks > 1) {
inode->extent_isize = legacymetasize;
inode->datalayout = EROFS_INODE_FLAT_COMPRESSION_LEGACY;
} else {
@@ -531,7 +543,17 @@ int z_erofs_compress_init(void)
algorithmtype[0] = ret; /* primary algorithm (head 0) */
algorithmtype[1] = 0; /* secondary algorithm (head 1) */
- mapheader.h_advise |= Z_EROFS_ADVISE_COMPACTED_2B;
+ mapheader.h_advise = 0;
+ if (!cfg.c_legacy_compress)
+ mapheader.h_advise |= Z_EROFS_ADVISE_COMPACTED_2B;
+ /*
+ * if big pcluster is enabled, an extra CBLKCNT lcluster index needs
+ * to be loaded in order to get those compressed block counts.
+ */
+ if (cfg.c_physical_clusterblks > 1) {
+ erofs_sb_set_big_pcluster();
+ mapheader.h_advise |= Z_EROFS_ADVISE_BIG_PCLUSTER_1;
+ }
mapheader.h_algorithmtype = algorithmtype[1] << 4 |
algorithmtype[0];
mapheader.h_clusterbits = LOG_BLOCK_SIZE - 12;
--
2.24.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [RFC PATCH v0 3/3] erofs-utils: fuse: support multiple block compression
2020-12-30 8:47 ` [RFC PATCH v0 0/3] erofs-utils: support multiple block compression Gao Xiang via Linux-erofs
2020-12-30 8:47 ` [RFC PATCH v0 1/3] erofs-utils: add -C# for the maximum size of pclusters Gao Xiang via Linux-erofs
2020-12-30 8:47 ` [RFC PATCH v0 2/3] erofs-utils: mkfs: support multiple block compression Gao Xiang via Linux-erofs
@ 2020-12-30 8:47 ` Gao Xiang via Linux-erofs
2020-12-30 10:12 ` [RFC PATCH v0 0/3] erofs-utils: " Gao Xiang
3 siblings, 0 replies; 5+ messages in thread
From: Gao Xiang via Linux-erofs @ 2020-12-30 8:47 UTC (permalink / raw)
To: linux-erofs
From: Gao Xiang <hsiangkao@aol.com>
Add multiple block compression runtime support for erofsfuse.
Signed-off-by: Gao Xiang <hsiangkao@aol.com>
---
lib/data.c | 4 +--
lib/zmap.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 68 insertions(+), 8 deletions(-)
diff --git a/lib/data.c b/lib/data.c
index 3781846743aa..b330a91e4e34 100644
--- a/lib/data.c
+++ b/lib/data.c
@@ -127,7 +127,7 @@ static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
};
bool partial;
unsigned int algorithmformat;
- char raw[EROFS_BLKSIZ];
+ char raw[1024 * EROFS_BLKSIZ];
end = offset + size;
while (end > offset) {
@@ -142,7 +142,7 @@ static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
continue;
}
- ret = dev_read(raw, map.m_pa, EROFS_BLKSIZ);
+ ret = dev_read(raw, map.m_pa, map.m_plen);
if (ret < 0)
return -EIO;
diff --git a/lib/zmap.c b/lib/zmap.c
index ee63de74cab2..096fd35cdeb3 100644
--- a/lib/zmap.c
+++ b/lib/zmap.c
@@ -14,7 +14,8 @@
int z_erofs_fill_inode(struct erofs_inode *vi)
{
- if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
+ if (!erofs_sb_has_big_pcluster() &&
+ vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
vi->z_advise = 0;
vi->z_algorithmtype[0] = 0;
vi->z_algorithmtype[1] = 0;
@@ -37,7 +38,8 @@ static int z_erofs_fill_inode_lazy(struct erofs_inode *vi)
if (vi->flags & EROFS_I_Z_INITED)
return 0;
- DBG_BUGON(vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
+ DBG_BUGON(!erofs_sb_has_big_pcluster() &&
+ vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
pos = round_up(iloc(vi->nid) + vi->inode_isize + vi->xattr_isize, 8);
ret = dev_read(buf, pos, sizeof(buf));
@@ -81,7 +83,7 @@ struct z_erofs_maprecorder {
u8 type;
u16 clusterofs;
u16 delta[2];
- erofs_blk_t pblk;
+ erofs_blk_t pblk, compressedlcs;
};
static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
@@ -130,6 +132,15 @@ static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
m->clusterofs = 1 << vi->z_logical_clusterbits;
m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
+ if (m->delta[0] & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+ if (!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ m->compressedlcs = m->delta[0] &
+ ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+ m->delta[0] = 1;
+ }
m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
break;
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
@@ -333,6 +344,51 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
return 0;
}
+static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
+ unsigned int initial_lcn)
+{
+ struct erofs_inode *const vi = m->inode;
+ struct erofs_map_blocks *const map = m->map;
+ const unsigned int lclusterbits = vi->z_logical_clusterbits;
+ unsigned long lcn;
+ int err;
+
+ DBG_BUGON(m->type != Z_EROFS_VLE_CLUSTER_TYPE_PLAIN &&
+ m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD);
+ if (!((map->m_flags & EROFS_MAP_ZIPPED) &&
+ (vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1))) {
+ map->m_plen = 1 << lclusterbits;
+ return 0;
+ }
+
+ lcn = m->lcn + 1;
+ if (lcn == initial_lcn && !m->compressedlcs)
+ m->compressedlcs = 2;
+
+ if (m->compressedlcs)
+ goto out;
+
+ err = z_erofs_load_cluster_from_disk(m, lcn);
+ if (err)
+ return err;
+
+ switch (m->type) {
+ case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+ DBG_BUGON(m->delta[0] != 1);
+ if (m->compressedlcs) {
+ break;
+ }
+ default:
+ erofs_err("cannot found CBLKCNT @ lcn %lu of nid %llu",
+ lcn, (unsigned long long)vi->nid);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+out:
+ map->m_plen = m->compressedlcs << lclusterbits;
+ return 0;
+}
+
int z_erofs_map_blocks_iter(struct erofs_inode *vi,
struct erofs_map_blocks *map)
{
@@ -343,6 +399,7 @@ int z_erofs_map_blocks_iter(struct erofs_inode *vi,
};
int err = 0;
unsigned int lclusterbits, endoff;
+ unsigned long initial_lcn;
unsigned long long ofs, end;
/* when trying to read beyond EOF, leave it unmapped */
@@ -359,10 +416,10 @@ int z_erofs_map_blocks_iter(struct erofs_inode *vi,
lclusterbits = vi->z_logical_clusterbits;
ofs = map->m_la;
- m.lcn = ofs >> lclusterbits;
+ initial_lcn = ofs >> lclusterbits;
endoff = ofs & ((1 << lclusterbits) - 1);
- err = z_erofs_load_cluster_from_disk(&m, m.lcn);
+ err = z_erofs_load_cluster_from_disk(&m, initial_lcn);
if (err)
goto out;
@@ -401,8 +458,11 @@ int z_erofs_map_blocks_iter(struct erofs_inode *vi,
}
map->m_llen = end - map->m_la;
- map->m_plen = 1 << lclusterbits;
map->m_pa = blknr_to_addr(m.pblk);
+
+ err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
+ if (err)
+ goto out;
map->m_flags |= EROFS_MAP_MAPPED;
out:
--
2.24.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [RFC PATCH v0 0/3] erofs-utils: support multiple block compression
2020-12-30 8:47 ` [RFC PATCH v0 0/3] erofs-utils: support multiple block compression Gao Xiang via Linux-erofs
` (2 preceding siblings ...)
2020-12-30 8:47 ` [RFC PATCH v0 3/3] erofs-utils: fuse: " Gao Xiang via Linux-erofs
@ 2020-12-30 10:12 ` Gao Xiang
3 siblings, 0 replies; 5+ messages in thread
From: Gao Xiang @ 2020-12-30 10:12 UTC (permalink / raw)
To: linux-erofs
On Wed, Dec 30, 2020 at 04:47:25PM +0800, Gao Xiang via Linux-erofs wrote:
> From: Gao Xiang <hsiangkao@aol.com>
>
> Hi folks,
>
> This is the first RFC patch of multiple block compression (including
> erofsfuse) after I carefully think over the on-disk design to support
> multiblock in-place decompression.
>
> Compression ratio results (POC, lz4hc, lz4-1.9.3, not final result):
> 1000000000 enwik9
> 621211648 enwik9_4k.squashfs.img
> 557858816 enwik9_4k.erofs.img
> 556191744 enwik9_8k.squashfs.img
> 502661120 enwik9_16k.squashfs.img
> 500723712 enwik9_8k.erofs.img
> 458784768 enwik9_32k.squashfs.img
> 453971968 enwik9_16k.erofs.img
> 422318080 enwik9_64k.squashfs.img
> 416686080 enwik9_32k.erofs.img
> 398204928 enwik9_128k.squashfs.img
> 395276288 enwik9_64k.erofs.img
I can also think out several compress strategies to control read amplification
but maintain a given C/R due to EROFS can compress variable-sized input data
to arbitary compressed block count for each pcluster, FYI.
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 5+ messages in thread