From: "Michael R. Hines" <mrhi...@us.ibm.com>
This functions allows you to perform your own per-QEMUFileOps
calculation for the value of 'max_size'.
For RDMA, this calculation artificially limits migration throughput
and needs to be done differently for high-throughput links.
Signed-off-by: Michael R. Hines <mrhi...@us.ibm.com>
---
include/migration/qemu-file.h | 12 ++++++++++++
migration.c | 3 ++-
savevm.c | 19 +++++++++++++++++++
3 files changed, 33 insertions(+), 1 deletion(-)
diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
index 70eb9bd..1803aeb 100644
--- a/include/migration/qemu-file.h
+++ b/include/migration/qemu-file.h
@@ -57,12 +57,22 @@ typedef int (QEMUFileGetFD)(void *opaque);
typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
int iovcnt, int64_t pos);
+/*
+ * This function allows override of how to calculate max_size
+ * after each iteration.
+ */
+typedef size_t (QEMUFileMaxSizeFunc)(QEMUFile *f, void *opaque,
+ uint64_t transferred_bytes,
+ uint64_t time_spent,
+ uint64_t max_downtime);
+
typedef struct QEMUFileOps {
QEMUFilePutBufferFunc *put_buffer;
QEMUFileGetBufferFunc *get_buffer;
QEMUFileCloseFunc *close;
QEMUFileGetFD *get_fd;
QEMUFileWritevBufferFunc *writev_buffer;
+ QEMUFileMaxSizeFunc *get_max_size;
} QEMUFileOps;
QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
@@ -81,6 +91,8 @@ void qemu_put_byte(QEMUFile *f, int v);
*/
void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size);
double qemu_get_mbps(void);
+size_t qemu_get_max_size(QEMUFile *f, uint64_t transferred_bytes,
+ uint64_t time_spent, uint64_t max_downtime);
static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v)
diff --git a/migration.c b/migration.c
index e2d73c4..48b5174 100644
--- a/migration.c
+++ b/migration.c
@@ -545,7 +545,8 @@ static void *migration_thread(void *opaque)
uint64_t transferred_bytes = qemu_ftell(s->file) - initial_bytes;
uint64_t time_spent = current_time - initial_time - sleep_time;
double bandwidth = transferred_bytes / time_spent;
- max_size = bandwidth * migrate_max_downtime() / 1000000;
+ max_size = qemu_get_max_size(s->file, transferred_bytes,
+ time_spent, migrate_max_downtime());
DPRINTF("transferred %" PRIu64 " time_spent %" PRIu64
" bandwidth %g max_size %" PRId64 "\n",
diff --git a/savevm.c b/savevm.c
index 6fcad19..60776e5 100644
--- a/savevm.c
+++ b/savevm.c
@@ -647,6 +647,25 @@ int qemu_get_fd(QEMUFile *f)
return -1;
}
+size_t qemu_get_max_size(QEMUFile *f, uint64_t transferred_bytes,
+ uint64_t time_spent, uint64_t max_downtime)
+{
+ if (time_spent) {
+ mbps = (((double) transferred_bytes * 8.0) /
+ ((double) time_spent / 1000.0)) / 1000.0 / 1000.0;
+ } else {
+ mbps = -1.0;
+ }
+
+ if (f->ops->get_max_size) {
+ return f->ops->get_max_size(f, f->opaque,
+ transferred_bytes, time_spent, max_downtime);
+ }
+
+ return ((double) (transferred_bytes / time_spent)) *
+ max_downtime / 1000000;
+}
+
/** Closes the file
*
* Returns negative error value if any error happened on previous operations or
--
1.7.10.4
