qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] Re: [RFC PATCH 05/20] Introduce put_vector() and get_vector


From: Anthony Liguori
Subject: [Qemu-devel] Re: [RFC PATCH 05/20] Introduce put_vector() and get_vector to QEMUFile and qemu_fopen_ops().
Date: Thu, 22 Apr 2010 14:28:30 -0500
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091209 Fedora/3.0-4.fc12 Lightning/1.0pre Thunderbird/3.0

On 04/21/2010 12:57 AM, Yoshiaki Tamura wrote:
QEMUFile currently doesn't support writev().  For sending multiple
data, such as pages, using writev() should be more efficient.

Signed-off-by: Yoshiaki Tamura<address@hidden>

Is there performance data that backs this up? Since QEMUFile uses a linear buffer for most operations that's limited to 16k, I suspect you wouldn't be able to observe a difference in practice.

Regards,

Anthony Liguori

---
  buffered_file.c |    2 +-
  hw/hw.h         |   16 ++++++++++++++++
  savevm.c        |   43 +++++++++++++++++++++++++------------------
  3 files changed, 42 insertions(+), 19 deletions(-)

diff --git a/buffered_file.c b/buffered_file.c
index 54dc6c2..187d1d4 100644
--- a/buffered_file.c
+++ b/buffered_file.c
@@ -256,7 +256,7 @@ QEMUFile *qemu_fopen_ops_buffered(void *opaque,
      s->wait_for_unfreeze = wait_for_unfreeze;
      s->close = close;

-    s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL,
+    s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL, NULL, NULL,
                               buffered_close, buffered_rate_limit,
                               buffered_set_rate_limit,
                             buffered_get_rate_limit);
diff --git a/hw/hw.h b/hw/hw.h
index fc9ed29..921cf90 100644
--- a/hw/hw.h
+++ b/hw/hw.h
@@ -23,6 +23,13 @@
  typedef int (QEMUFilePutBufferFunc)(void *opaque, const uint8_t *buf,
                                      int64_t pos, int size);

+/* This function writes a chunk of vector to a file at the given position.
+ * The pos argument can be ignored if the file is only being used for
+ * streaming.
+ */
+typedef int (QEMUFilePutVectorFunc)(void *opaque, struct iovec *iov,
+                                    int64_t pos, int iovcnt);
+
  /* Read a chunk of data from a file at the given position.  The pos argument
   * can be ignored if the file is only be used for streaming.  The number of
   * bytes actually read should be returned.
@@ -30,6 +37,13 @@ typedef int (QEMUFilePutBufferFunc)(void *opaque, const 
uint8_t *buf,
  typedef int (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
                                      int64_t pos, int size);

+/* Read a chunk of vector from a file at the given position.  The pos argument
+ * can be ignored if the file is only be used for streaming.  The number of
+ * bytes actually read should be returned.
+ */
+typedef int (QEMUFileGetVectorFunc)(void *opaque, struct iovec *iov,
+                                    int64_t pos, int iovcnt);
+
  /* Close a file and return an error code */
  typedef int (QEMUFileCloseFunc)(void *opaque);

@@ -46,7 +60,9 @@ typedef size_t (QEMUFileSetRateLimit)(void *opaque, size_t 
new_rate);
  typedef size_t (QEMUFileGetRateLimit)(void *opaque);

  QEMUFile *qemu_fopen_ops(void *opaque, QEMUFilePutBufferFunc *put_buffer,
+                         QEMUFilePutVectorFunc *put_vector,
                           QEMUFileGetBufferFunc *get_buffer,
+                         QEMUFileGetVectorFunc *get_vector,
                           QEMUFileCloseFunc *close,
                           QEMUFileRateLimit *rate_limit,
                           QEMUFileSetRateLimit *set_rate_limit,
diff --git a/savevm.c b/savevm.c
index 490ab70..944e788 100644
--- a/savevm.c
+++ b/savevm.c
@@ -162,7 +162,9 @@ void qemu_announce_self(void)

  struct QEMUFile {
      QEMUFilePutBufferFunc *put_buffer;
+    QEMUFilePutVectorFunc *put_vector;
      QEMUFileGetBufferFunc *get_buffer;
+    QEMUFileGetVectorFunc *get_vector;
      QEMUFileCloseFunc *close;
      QEMUFileRateLimit *rate_limit;
      QEMUFileSetRateLimit *set_rate_limit;
@@ -263,11 +265,11 @@ QEMUFile *qemu_popen(FILE *stdio_file, const char *mode)
      s->stdio_file = stdio_file;

      if(mode[0] == 'r') {
-        s->file = qemu_fopen_ops(s, NULL, stdio_get_buffer, stdio_pclose,
-                                NULL, NULL, NULL);
+        s->file = qemu_fopen_ops(s, NULL, NULL, stdio_get_buffer,
+                 NULL, stdio_pclose, NULL, NULL, NULL);
      } else {
-        s->file = qemu_fopen_ops(s, stdio_put_buffer, NULL, stdio_pclose,
-                                NULL, NULL, NULL);
+        s->file = qemu_fopen_ops(s, stdio_put_buffer, NULL, NULL, NULL,
+                 stdio_pclose, NULL, NULL, NULL);
      }
      return s->file;
  }
@@ -312,11 +314,11 @@ QEMUFile *qemu_fdopen(int fd, const char *mode)
          goto fail;

      if(mode[0] == 'r') {
-        s->file = qemu_fopen_ops(s, NULL, stdio_get_buffer, stdio_fclose,
-                                NULL, NULL, NULL);
+        s->file = qemu_fopen_ops(s, NULL, NULL, stdio_get_buffer, NULL,
+                 stdio_fclose, NULL, NULL, NULL);
      } else {
-        s->file = qemu_fopen_ops(s, stdio_put_buffer, NULL, stdio_fclose,
-                                NULL, NULL, NULL);
+        s->file = qemu_fopen_ops(s, stdio_put_buffer, NULL, NULL, NULL,
+                 stdio_fclose, NULL, NULL, NULL);
      }
      return s->file;

@@ -330,8 +332,8 @@ QEMUFile *qemu_fopen_socket(int fd)
      QEMUFileSocket *s = qemu_mallocz(sizeof(QEMUFileSocket));

      s->fd = fd;
-    s->file = qemu_fopen_ops(s, NULL, socket_get_buffer, socket_close,
-                            NULL, NULL, NULL);
+    s->file = qemu_fopen_ops(s, NULL, NULL, socket_get_buffer, NULL,
+                             socket_close, NULL, NULL, NULL);
      return s->file;
  }

@@ -368,11 +370,11 @@ QEMUFile *qemu_fopen(const char *filename, const char 
*mode)
          goto fail;

      if(mode[0] == 'w') {
-        s->file = qemu_fopen_ops(s, file_put_buffer, NULL, stdio_fclose,
-                                NULL, NULL, NULL);
+        s->file = qemu_fopen_ops(s, file_put_buffer, NULL, NULL, NULL,
+                  stdio_fclose, NULL, NULL, NULL);
      } else {
-        s->file = qemu_fopen_ops(s, NULL, file_get_buffer, stdio_fclose,
-                              NULL, NULL, NULL);
+        s->file = qemu_fopen_ops(s, NULL, NULL, file_get_buffer, NULL,
+                  stdio_fclose, NULL, NULL, NULL);
      }
      return s->file;
  fail:
@@ -400,13 +402,16 @@ static int bdrv_fclose(void *opaque)
  static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int is_writable)
  {
      if (is_writable)
-        return qemu_fopen_ops(bs, block_put_buffer, NULL, bdrv_fclose,
-                             NULL, NULL, NULL);
-    return qemu_fopen_ops(bs, NULL, block_get_buffer, bdrv_fclose, NULL, NULL, 
NULL);
+        return qemu_fopen_ops(bs, block_put_buffer, NULL, NULL, NULL,
+                  bdrv_fclose, NULL, NULL, NULL);
+    return qemu_fopen_ops(bs, NULL, NULL, block_get_buffer, NULL, bdrv_fclose, 
NULL, NULL, NULL);
  }

-QEMUFile *qemu_fopen_ops(void *opaque, QEMUFilePutBufferFunc *put_buffer,
+QEMUFile *qemu_fopen_ops(void *opaque,
+                         QEMUFilePutBufferFunc *put_buffer,
+                         QEMUFilePutVectorFunc *put_vector,
                           QEMUFileGetBufferFunc *get_buffer,
+                         QEMUFileGetVectorFunc *get_vector,
                           QEMUFileCloseFunc *close,
                           QEMUFileRateLimit *rate_limit,
                           QEMUFileSetRateLimit *set_rate_limit,
@@ -418,7 +423,9 @@ QEMUFile *qemu_fopen_ops(void *opaque, 
QEMUFilePutBufferFunc *put_buffer,

      f->opaque = opaque;
      f->put_buffer = put_buffer;
+    f->put_vector = put_vector;
      f->get_buffer = get_buffer;
+    f->get_vector = get_vector;
      f->close = close;
      f->rate_limit = rate_limit;
      f->set_rate_limit = set_rate_limit;





reply via email to

[Prev in Thread] Current Thread [Next in Thread]