Re: [Qemu-block] [PATCH 4/4] block/qcow2: add zlib-fast compression algorithm

2017-06-27 Thread Peter Lieven 

Am 27.06.2017 um 14:53 schrieb Eric Blake:

On 06/27/2017 07:34 AM, Peter Lieven wrote:

this adds support for optimized zlib settings which almost

Start sentences with a capital.


tripples the compression speed while maintaining about

s/tripples/triples/


the same compressed size.

Signed-off-by: Peter Lieven 
---
  block/qcow2-cluster.c |  3 ++-
  block/qcow2.c | 11 +--
  block/qcow2.h |  1 +
  qemu-img.texi |  1 +
  4 files changed, 13 insertions(+), 3 deletions(-)

+++ b/block/qcow2.h
@@ -173,6 +173,7 @@ typedef struct Qcow2UnknownHeaderExtension {
  enum {
  QCOW2_COMPRESSION_ZLIB  = 0xC0318301,
  QCOW2_COMPRESSION_LZO   = 0xC0318302,
+QCOW2_COMPRESSION_ZLIB_FAST = 0xC0318303,

Back to my comments on 1/4 - we MUST first get the qcow2 specification
right, rather than adding undocumented headers in the code.  And I still
think you only need one variable-length header extension for covering
all possible algorithms, rather than one header per algorithm.  Let's
get the spec right first, before worrying about the code implementing
the spec.



Okay, I think someone came up with the idea to have an optional
header per algorithm, but you are right one header with an optional
parameter payload will also do.

I will split the spec change to a separate patch in V2 to make it easier
to respin.

Thanks,
Peter

Re: [Qemu-block] [PATCH 4/4] block/qcow2: add zlib-fast compression algorithm

2017-06-27 Thread Eric Blake 
On 06/27/2017 07:34 AM, Peter Lieven wrote:
> this adds support for optimized zlib settings which almost

Start sentences with a capital.

> tripples the compression speed while maintaining about

s/tripples/triples/

> the same compressed size.
> 
> Signed-off-by: Peter Lieven 
> ---
>  block/qcow2-cluster.c |  3 ++-
>  block/qcow2.c | 11 +--
>  block/qcow2.h |  1 +
>  qemu-img.texi |  1 +
>  4 files changed, 13 insertions(+), 3 deletions(-)
> 

> +++ b/block/qcow2.h
> @@ -173,6 +173,7 @@ typedef struct Qcow2UnknownHeaderExtension {
>  enum {
>  QCOW2_COMPRESSION_ZLIB  = 0xC0318301,
>  QCOW2_COMPRESSION_LZO   = 0xC0318302,
> +QCOW2_COMPRESSION_ZLIB_FAST = 0xC0318303,

Back to my comments on 1/4 - we MUST first get the qcow2 specification
right, rather than adding undocumented headers in the code.  And I still
think you only need one variable-length header extension for covering
all possible algorithms, rather than one header per algorithm.  Let's
get the spec right first, before worrying about the code implementing
the spec.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.   +1-919-301-3266
Virtualization:  qemu.org | libvirt.org



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[Qemu-block] [PATCH 4/4] block/qcow2: add zlib-fast compression algorithm

2017-06-27 Thread Peter Lieven 
this adds support for optimized zlib settings which almost
tripples the compression speed while maintaining about
the same compressed size.

Signed-off-by: Peter Lieven 
---
 block/qcow2-cluster.c |  3 ++-
 block/qcow2.c | 11 +--
 block/qcow2.h |  1 +
 qemu-img.texi |  1 +
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index ecb059b..d8e2378 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1532,6 +1532,7 @@ static int decompress_buffer(uint8_t *out_buf, int 
out_buf_size,
 
 switch (compression_algorithm_id) {
 case QCOW2_COMPRESSION_ZLIB:
+case QCOW2_COMPRESSION_ZLIB_FAST:
 memset(strm, 0, sizeof(*strm));
 
 strm->next_in = (uint8_t *)buf;
@@ -1539,7 +1540,7 @@ static int decompress_buffer(uint8_t *out_buf, int 
out_buf_size,
 strm->next_out = out_buf;
 strm->avail_out = out_buf_size;
 
-ret = inflateInit2(strm, -12);
+ret = inflateInit2(strm, -15);
 if (ret != Z_OK) {
 return -1;
 }
diff --git a/block/qcow2.c b/block/qcow2.c
index bd65582..f07d8f0 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -87,6 +87,8 @@ static uint32_t is_compression_algorithm_supported(char 
*algorithm)
 /* no algorithm means the old default of zlib compression
  * with 12 window bits */
 return QCOW2_COMPRESSION_ZLIB;
+} else if (!strcmp(algorithm, "zlib-fast")) {
+return QCOW2_COMPRESSION_ZLIB_FAST;
 #ifdef CONFIG_LZO
 } else if (!strcmp(algorithm, "lzo")) {
 return QCOW2_COMPRESSION_LZO;
@@ -2722,6 +2724,7 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, 
uint64_t offset,
 QEMUIOVector hd_qiov;
 struct iovec iov;
 z_stream strm;
+int z_level = Z_DEFAULT_COMPRESSION, z_windowBits = -12;
 int ret, out_len = 0;
 uint8_t *buf, *out_buf = NULL, *local_buf = NULL, *work_buf = NULL;
 uint64_t cluster_offset;
@@ -2749,13 +2752,17 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, 
uint64_t offset,
 }
 
 switch (s->compression_algorithm_id) {
+case QCOW2_COMPRESSION_ZLIB_FAST:
+z_level = Z_BEST_SPEED;
+z_windowBits = -15;
+/* fall-through */
 case QCOW2_COMPRESSION_ZLIB:
 out_buf = g_malloc(s->cluster_size);
 
 /* best compression, small window, no zlib header */
 memset(&strm, 0, sizeof(strm));
-ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
-   Z_DEFLATED, -12,
+ret = deflateInit2(&strm, z_level,
+   Z_DEFLATED, z_windowBits,
9, Z_DEFAULT_STRATEGY);
 if (ret != 0) {
 ret = -EINVAL;
diff --git a/block/qcow2.h b/block/qcow2.h
index 716012c..a89f986 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -173,6 +173,7 @@ typedef struct Qcow2UnknownHeaderExtension {
 enum {
 QCOW2_COMPRESSION_ZLIB  = 0xC0318301,
 QCOW2_COMPRESSION_LZO   = 0xC0318302,
+QCOW2_COMPRESSION_ZLIB_FAST = 0xC0318303,
 };
 
 enum {
diff --git a/qemu-img.texi b/qemu-img.texi
index 043c1ba..83a5db2 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -627,6 +627,7 @@ The following options are available if support for the 
respective libraries
 has been enabled at compile time:
 
zlibUses standard zlib compression (default)
+   zlib-fast   Uses zlib compression with optimized compression parameters
lzo Uses LZO1X compression
 
 The compression algorithm can only be defined at image create time and cannot
-- 
1.9.1