diff mbox

[v2,3/3] Btrfs: heuristic add byte core set calculation

Message ID 20170726124958.18837-4-nefelim4ag@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Timofey Titovets July 26, 2017, 12:49 p.m. UTC
Calculate byte core set for data sample:
Sort bucket's numbers in decreasing order
Count how many numbers use 90% of sample
If core set are low (<=25%), data are easily compressible
If core set high (>=80%), data are not compressible

Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com>
---
 fs/btrfs/compression.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/compression.h |  2 ++
 2 files changed, 59 insertions(+)

--
2.13.3
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Comments

kernel test robot July 29, 2017, 5:52 a.m. UTC | #1
Hi Timofey,

[auto build test ERROR on next-20170724]
[cannot apply to btrfs/next v4.13-rc2 v4.13-rc1 v4.12 v4.13-rc2]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Timofey-Titovets/Btrfs-populate-heuristic-with-detection-logic/20170729-061208
config: i386-randconfig-n0-201730 (attached as .config)
compiler: gcc-4.8 (Debian 4.8.4-1) 4.8.4
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   fs/btrfs/compression.o: In function `btrfs_compress_heuristic':
>> compression.c:(.text+0x2208): undefined reference to `__udivdi3'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
kernel test robot July 29, 2017, 11:43 a.m. UTC | #2
Hi Timofey,

[auto build test ERROR on next-20170724]
[cannot apply to btrfs/next v4.13-rc2 v4.13-rc1 v4.12 v4.13-rc2]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Timofey-Titovets/Btrfs-populate-heuristic-with-detection-logic/20170729-061208
config: arm-arm5 (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm 

All errors (new ones prefixed by >>):

>> ERROR: "__aeabi_uldivmod" [fs/btrfs/btrfs.ko] undefined!

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
Timofey Titovets July 29, 2017, 1:30 p.m. UTC | #3
2017-07-29 14:43 GMT+03:00 kbuild test robot <lkp@intel.com>:
> Hi Timofey,
>
> [auto build test ERROR on next-20170724]
> [cannot apply to btrfs/next v4.13-rc2 v4.13-rc1 v4.12 v4.13-rc2]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url:    https://github.com/0day-ci/linux/commits/Timofey-Titovets/Btrfs-populate-heuristic-with-detection-logic/20170729-061208
> config: arm-arm5 (attached as .config)
> compiler: arm-linux-gnueabi-gcc (Debian 6.1.1-9) 6.1.1 20160705
> reproduce:
>         wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # save the attached .config to linux build tree
>         make.cross ARCH=arm
>
> All errors (new ones prefixed by >>):
>
>>> ERROR: "__aeabi_uldivmod" [fs/btrfs/btrfs.ko] undefined!
>
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

I will fix 64bit division and resend patch set

Thanks.
diff mbox

Patch

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 1429b11f2c5f..314cbdd8d175 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -1069,6 +1069,42 @@  static inline int byte_set_size(const struct heuristic_bucket_item *bucket)
 	return byte_set_size;
 }

+/* For bucket sorting */
+static inline int heuristic_bucket_compare(const void *lv, const void *rv)
+{
+	struct heuristic_bucket_item *l = (struct heuristic_bucket_item *)(lv);
+	struct heuristic_bucket_item *r = (struct heuristic_bucket_item *)(rv);
+
+	return r->count - l->count;
+}
+
+/*
+ * Byte Core set size
+ * How many bytes use 90% of sample
+ */
+static inline int byte_core_set_size(struct heuristic_bucket_item *bucket,
+				     u32 core_set_threshold)
+{
+	int a = 0;
+	u32 coreset_sum = 0;
+
+	for (; a < BTRFS_HEURISTIC_BYTE_CORE_SET_LOW; a++)
+		coreset_sum += bucket[a].count;
+
+	if (coreset_sum > core_set_threshold)
+		return a;
+
+	for (; a < BTRFS_HEURISTIC_BYTE_CORE_SET_HIGH; a++) {
+		if (bucket[a].count == 0)
+			break;
+		coreset_sum += bucket[a].count;
+		if (coreset_sum > core_set_threshold)
+			break;
+	}
+
+	return a;
+}
+
 /*
  * Compression heuristic.
  *
@@ -1092,6 +1128,8 @@  int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end)
 	struct heuristic_bucket_item *bucket;
 	int a, b, ret;
 	u8 symbol, *input_data;
+	u32 core_set_threshold;
+	u64 input_size = start - end;

 	ret = 1;

@@ -1123,6 +1161,25 @@  int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end)
 		goto out;
 	}

+	/* Sort in reverse order */
+	sort(bucket, BTRFS_HEURISTIC_BUCKET_SIZE,
+	     sizeof(struct heuristic_bucket_item), &heuristic_bucket_compare,
+	     NULL);
+
+	core_set_threshold = input_size*90/BTRFS_HEURISTIC_ITER_OFFSET/100;
+	core_set_threshold *= BTRFS_HEURISTIC_READ_SIZE;
+
+	a = byte_core_set_size(bucket, core_set_threshold);
+	if (a <= BTRFS_HEURISTIC_BYTE_CORE_SET_LOW) {
+		ret = 2;
+		goto out;
+	}
+
+	if (a >= BTRFS_HEURISTIC_BYTE_CORE_SET_HIGH) {
+		ret = 0;
+		goto out;
+	}
+
 out:
 	kfree(bucket);
 	return ret;
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 03857967815a..0fcd1a485adb 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -139,6 +139,8 @@  struct heuristic_bucket_item {
 #define BTRFS_HEURISTIC_ITER_OFFSET 256
 #define BTRFS_HEURISTIC_BUCKET_SIZE 256
 #define BTRFS_HEURISTIC_BYTE_SET_THRESHOLD 64
+#define BTRFS_HEURISTIC_BYTE_CORE_SET_LOW  BTRFS_HEURISTIC_BYTE_SET_THRESHOLD
+#define BTRFS_HEURISTIC_BYTE_CORE_SET_HIGH 200 // 80%

 int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);