| Message ID | 1363963683-26157-8-git-send-email-owasserm@redhat.com |
|---|---|
| State | New |
| Headers | show |
Am 22.03.2013 um 15:48 hat Orit Wasserman geschrieben: > This will remove an unneeded copy of guest memory pages. > For the page header and device state we still copy the data to the > static buffer the other option is to allocate the memory on demand > which is more expensive. > > Signed-off-by: Orit Wasserman <owasserm@redhat.com> This seems to have killed savevm performance. I noticed that qemu-iotests case 007 took forever on my test box (882 seconds instead of something like 10 seconds). It can be reproduced by this script: export MALLOC_PERTURB_=11 qemu-img create -f qcow2 -o compat=1.1 test.qcow2 1M time qemu-system-x86_64 -nographic -hda $TEST_IMG -serial none -monitor stdio <<EOF savevm test quit EOF This used to take about 0.6s for me, after this patch it's around 10s. Kevin
diff --git a/arch_init.c b/arch_init.c index 98e2bc6..aa56a20 100644 --- a/arch_init.c +++ b/arch_init.c @@ -481,7 +481,7 @@ static int ram_save_block(QEMUFile *f, bool last_stage) /* XBZRLE overflow or normal page */ if (bytes_sent == -1) { bytes_sent = save_block_hdr(f, block, offset, cont, RAM_SAVE_FLAG_PAGE); - qemu_put_buffer(f, p, TARGET_PAGE_SIZE); + qemu_put_buffer_async(f, p, TARGET_PAGE_SIZE); bytes_sent += TARGET_PAGE_SIZE; acct_info.norm_pages++; }
This will remove an unneeded copy of guest memory pages. For the page header and device state we still copy the data to the static buffer the other option is to allocate the memory on demand which is more expensive. Signed-off-by: Orit Wasserman <owasserm@redhat.com> --- arch_init.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)