diff options
author | Paolo Bonzini <pbonzini@redhat.com> | 2013-04-08 13:29:55 +0200 |
---|---|---|
committer | Juan Quintela <quintela@redhat.com> | 2013-04-09 15:00:13 +0200 |
commit | 7ce51f1b8157a2aa6bd3945bba9904442d3c3cdd (patch) | |
tree | 6c13c0a135b4c917c75f13365221fe4dd87c3edd /savevm.c | |
parent | af74db72d33e4776d7d1430b57d0bf065a6f03df (diff) | |
download | qemu-7ce51f1b8157a2aa6bd3945bba9904442d3c3cdd.zip qemu-7ce51f1b8157a2aa6bd3945bba9904442d3c3cdd.tar.gz qemu-7ce51f1b8157a2aa6bd3945bba9904442d3c3cdd.tar.bz2 |
migration: use a single I/O operation when writev_buffer is not defined
The recent patches to use vectored I/O for RAM migration caused a
regression in savevm speed. To restore previous performance,
add data to the buffer in qemu_put_buffer_async whenever writev_buffer
is not available in the QEMUFile.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'savevm.c')
-rw-r--r-- | savevm.c | 49 |
1 files changed, 34 insertions, 15 deletions
@@ -525,27 +525,24 @@ static void qemu_file_set_error(QEMUFile *f, int ret) static void qemu_fflush(QEMUFile *f) { ssize_t ret = 0; - int i = 0; if (!f->ops->writev_buffer && !f->ops->put_buffer) { return; } - if (f->is_write && f->iovcnt > 0) { + if (f->is_write) { if (f->ops->writev_buffer) { - ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt); - if (ret >= 0) { - f->pos += ret; + if (f->iovcnt > 0) { + ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt); } } else { - for (i = 0; i < f->iovcnt && ret >= 0; i++) { - ret = f->ops->put_buffer(f->opaque, f->iov[i].iov_base, f->pos, - f->iov[i].iov_len); - if (ret >= 0) { - f->pos += ret; - } + if (f->buf_index > 0) { + ret = f->ops->put_buffer(f->opaque, f->buf, f->pos, f->buf_index); } } + if (ret >= 0) { + f->pos += ret; + } f->buf_index = 0; f->iovcnt = 0; } @@ -640,6 +637,11 @@ static void add_to_iovec(QEMUFile *f, const uint8_t *buf, int size) void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size) { + if (!f->ops->writev_buffer) { + qemu_put_buffer(f, buf, size); + return; + } + if (f->last_error) { return; } @@ -673,8 +675,17 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size) if (l > size) l = size; memcpy(f->buf + f->buf_index, buf, l); - f->buf_index += l; - qemu_put_buffer_async(f, f->buf + (f->buf_index - l), l); + f->bytes_xfer += size; + if (f->ops->writev_buffer) { + add_to_iovec(f, f->buf + f->buf_index, l); + f->buf_index += l; + } else { + f->is_write = 1; + f->buf_index += l; + if (f->buf_index == IO_BUF_SIZE) { + qemu_fflush(f); + } + } if (qemu_file_get_error(f)) { break; } @@ -697,8 +708,16 @@ void qemu_put_byte(QEMUFile *f, int v) f->buf[f->buf_index] = v; f->bytes_xfer++; - add_to_iovec(f, f->buf + f->buf_index, 1); - f->buf_index++; + if (f->ops->writev_buffer) { + add_to_iovec(f, f->buf + f->buf_index, 1); + f->buf_index++; + } else { + f->is_write = 1; + f->buf_index++; + if (f->buf_index == IO_BUF_SIZE) { + qemu_fflush(f); + } + } } static void qemu_file_skip(QEMUFile *f, int size) |