Laszlo spotted and studied this wasteful "if". He pointed out:
The original virtio_blk_free_request needed an "if" as it accesses one
field, since 671ec3f056 ("virtio-blk: Convert VirtIOBlockReq.elem to
pointer", 2014-06-11); later on in f897bf751f ("virtio-blk: embed
VirtQueueElement in VirtIOBlockReq", 2014-07-09) the field became
embedded, so the "if" became unnecessary (at which point we were using
g_slice_free(), but it is the same.
Now drop it.
Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
This makes all device emulations with a qdev drive property request
permissions on their BlockBackend. The only thing we block at this point
is resizing images for some devices that can't support it.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-16-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-15-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This covers both file descriptor callbacks and polling callbacks,
since they execute related code.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-14-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
In virtio_queue_host_notifier_aio_poll, not all "!virtio_queue_empty()"
cases are making true progress.
Currently the offending one is virtio-scsi event queue, whose handler
does nothing if no event is pending. As a result aio_poll() will spin on
the "non-empty" VQ and take 100% host CPU.
Fix this by reporting actual progress from virtio queue aio handlers.
Reported-by: Ed Swierk <eswierk@skyportsystems.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Tested-by: Ed Swierk <eswierk@skyportsystems.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Currently, all virtio devices bypass IOMMU completely. This is because
address_space_memory is assumed and used during DMA emulation. This
patch converts the virtio core API to use DMA API. This idea is
- introducing a new transport specific helper to query the dma address
space. (only pci version is implemented).
- query and use this address space during virtio device guest memory
accessing when iommu platform (VIRTIO_F_IOMMU_PLATFORM) was enabled
for this device.
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The guest does not need to kick the virtqueue while we are processing
it. This reduces the number of vmexits during periods of heavy I/O.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-8-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Override start_ioeventfd and stop_ioeventfd to start/stop the
whole dataplane logic. This has some positive side effects:
- no need anymore for virtio_add_queue_aio (i.e. a revert of
commit 0ff841f6d1)
- no need anymore to switch from generic ioeventfd handlers to
dataplane
It detects some errors better:
$ qemu-system-x86_64 -object iothread,id=io \
-drive id=null,file=null-aio://,if=none,format=raw \
-device virtio-blk-pci,ioeventfd=off,iothread=io,drive=null
qemu-system-x86_64: -device virtio-blk-pci,ioeventfd=off,iothread=io,drive=null:
ioeventfd is required for iothread
while previously it would have started just fine.
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Now all the usages of the old version of VMSTATE_VIRTIO_DEVICE are gone,
so we can get rid of the conditionals, and the old macro.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Use the new VMSTATE_VIRTIO_DEVICE macro.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
All these errors are caused by a buggy guest: QEMU should not exit.
With this patch, if virtio_blk_handle_request() detects a buggy request, it
marks the device as broken and returns an error to the caller so it takes
appropriate action.
In the case of virtio_blk_handle_vq(), we detach the request from the
virtqueue, free its allocated memory and stop popping new requests.
We don't need to bother about multireq since virtio_blk_handle_request()
errors out early and mrb.num_reqs == 0.
In the case of virtio_blk_dma_restart_bh(), we need to detach and free all
queued requests as well.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Some functions that were called from the dataplane code are now only used
locally:
virtio_blk_init_request()
virtio_blk_handle_request()
virtio_blk_submit_multireq()
since commit "03de2f527499 virtio-blk: do not use vring in dataplane", and
virtio_blk_free_request()
since commit "6aa46d8ff1ee virtio: move VirtQueueElement at the beginning
of the structs".
This patch converts them to static.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Make sure to unmap the scatter-gather list and decrement vq->inuse
before freeing requests in virtio_blk_reset().
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Ladi Prosek <lprosek@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The old one is confusing with @virtio_device_info in virtio.c,
so make it more appropriate.
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Message-id: 1470214147-32560-1-git-send-email-xiecl.fnst@cn.fujitsu.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This is stale after commit 6e40b3bf (virtio-blk: Use blk_drain() to
drain IO requests), remove it.
Suggested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1470278654-13525-3-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
At system_reset, there is no point in retrying the queued request,
because the driver that issued the request won't be around any more.
Analyzed-by: Laszlo Ersek <lersek@redhat.com>
Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1470278654-13525-2-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Forcibly convert it to a vmstate wrapper; proper conversion
comes later.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
AIO based handler is more appropriate here because it will then
cooperate with bdrv_drained_begin/end. It is needed by the coming
revert patch.
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
The rerror/werror policies are implemented in the devices, so that's
where they should be configured. In comparison to the old options in
-drive, the qdev properties are only added to those devices that
actually support them.
If the option isn't given (or "auto" is specified), the setting of the
BlockBackend is used for compatibility with the old options. For block
jobs, "auto" is the same as "enospc".
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
As cache.writeback is a BlockBackend property and as such more related
to the guest device than the BlockDriverState, we already removed it
from the blockdev-add interface. This patch adds the new way to set it,
as a qdev property of the corresponding guest device.
For example: -drive if=none,file=test.img,node-name=img
-device ide-hd,drive=img,write-cache=off
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Sector-based limits are awkward to think about; in our on-going
quest to move to byte-based interfaces, convert max_transfer_length
and opt_transfer_length. Rename them (dropping the _length suffix)
so that the compiler will help us catch the change in semantics
across any rebased code, and improve the documentation. Use unsigned
values, so that we don't have to worry about negative values and
so that bit-twiddling is easier; however, we are still constrained
by 2^31 of signed int in most APIs.
When a value comes from an external source (iscsi and raw-posix),
sanitize the results to ensure that opt_transfer is a power of 2.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Making all callers special-case 0 as unlimited is awkward,
and we DO have a hard maximum of BDRV_REQUEST_MAX_SECTORS given
our current block layer API limits.
In the case of scsi, this means that we now always advertise a
limit to the guest, even in cases where the underlying layers
previously use 0 for no inherent limit beyond the block layer.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Multiqueue virtio-blk can be enabled as follows:
qemu -device virtio-blk-pci,num-queues=8
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1466511196-12612-8-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Add a field for the virtqueue index when migrating the s->rq request
list. The new field is only needed when num_queues > 1. Existing QEMUs
are unaffected by this change and therefore virtio-blk migration stays
compatible.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1466511196-12612-6-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Multiqueue requires that each request knows to which virtqueue it
belongs.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1466511196-12612-5-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Let the virtio_blk_data_plane_notify() caller decide which virtqueue to
notify. This will allow the function to be used with multiqueue.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1466511196-12612-4-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The num_queues field is always 1 for the time being. A later patch will
make it a configurable device property so that multiqueue can be
enabled.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1466511196-12612-2-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This reverts commit 10a06fd65f.
Dataplane has used the same virtqueue code as non-dataplane since
commits e24a47c5b7 ("virtio-scsi: do not
use vring in dataplane") and 03de2f5274
("virtio-blk: do not use vring in dataplane"). It is no longer
necessary to stop dataplane in order to sync state since there is no
duplicated virtqueue state.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Message-id: 1466503331-9831-1-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Sector-based blk_aio_readv() and blk_aio_writev() should die; switch
to byte-based blk_aio_preadv() and blk_aio_pwritev() instead.
The trace is modified at the same time, and nb_sectors is now
unused. Fix a comment typo while in the vicinity.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In addition to handling IO in vcpu thread and in io thread, dataplane
introduces yet another mode: handling it by AioContext.
This reuses the same handler as previous modes, which triggers races as
these were not designed to be reentrant. Use a separate handler just
for aio, and disable regular handlers when dataplane is active.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
We must not call virtio_blk_data_plane_notify if dataplane is
disabled: we would hit a segmentation fault in notify_guest_bh as
s->guest_notifier has not been setup and is NULL.
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Commit 57cb38b included qapi/error.h into qemu/osdep.h to get the
Error typedef. Since then, we've moved to include qemu/osdep.h
everywhere. Its file comment explains: "To avoid getting into
possible circular include dependencies, this file should not include
any other QEMU headers, with the exceptions of config-host.h,
compiler.h, os-posix.h and os-win32.h, all of which are doing a
similar job to this file and are under similar constraints."
qapi/error.h doesn't do a similar job, and it doesn't adhere to
similar constraints: it includes qapi-types.h. That's in excess of
100KiB of crap most .c files don't actually need.
Add the typedef to qemu/typedefs.h, and include that instead of
qapi/error.h. Include qapi/error.h in .c files that need it and don't
get it now. Include qapi-types.h in qom/object.h for uint16List.
Update scripts/clean-includes accordingly. Update it further to match
reality: replace config.h by config-target.h, add sysemu/os-posix.h,
sysemu/os-win32.h. Update the list of includes in the qemu/osdep.h
comment quoted above similarly.
This reduces the number of objects depending on qapi/error.h from "all
of them" to less than a third. Unfortunately, the number depending on
qapi-types.h shrinks only a little. More work is needed for that one.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
[Fix compilation without the spice devel packages. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
In disabled mode, virtio-blk dataplane seems to be enabled, but flow
actually goes through the normal virtio path. This patch simplifies a bit
the handling of disabled mode. In disabled mode, virtio_blk_handle_output
might be called even if s->dataplane is not NULL.
This is a bit tricky, because the current check for s->dataplane will
always trigger, causing a continuous stream of calls to
virtio_blk_data_plane_start. Unfortunately, these calls will not
do anything. To fix this, set the "started" flag even in disabled
mode, and skip virtio_blk_data_plane_start if the started flag is true.
The resulting changes also prepare the code for the next patch, were
virtio-blk dataplane will reuse the same virtio_blk_handle_output function
as "regular" virtio-blk.
Because struct VirtIOBlockDataPlane is opaque in virtio-blk.c, we have
to move s->dataplane->started inside struct VirtIOBlock.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Move allocation to virtio functions also when loading/saving a
VirtQueueElement. This will also let the load/save functions
keep backwards compatibility when the VirtQueueElement layout
is changed.
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The return code of virtqueue_pop/vring_pop is unused except to check for
errors or 0. We can thus easily move allocation inside the functions
and just return a pointer to the VirtQueueElement.
The advantage is that we will be able to allocate only the space that
is needed for the actual size of the s/g list instead of the full
VIRTQUEUE_MAX_SIZE items. Currently VirtQueueElement takes about 48K
of memory, and this kind of allocation puts a lot of stress on malloc.
By cutting the size by two or three orders of magnitude, malloc can
use much more efficient algorithms.
The patch is pretty large, but changes to each device are testable
more or less independently. Splitting it would mostly add churn.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.
This commit was created with scripts/clean-includes.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Request merging must not result in a huge request that exceeds the
maximum number of iovec elements. Use BlockLimits.max_iov instead of
hardcoding IOV_MAX.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
1. avoid possible superflous checking
2. make code more robustness
["make code more robustness" refers to avoiding integer
underflows/overflows.
--Stefan]
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Message-id: 1447207166-12612-1-git-send-email-arei.gonglei@huawei.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The official way of enabling dataplane is through the "iothread"
property that references an iothread object created by "-object
iothread". Since the old "x-data-plane=on" way now even crashes, it's
probably easier to just drop it:
$ qemu-system-x86_64 -drive file=null-co://,id=d0,if=none \
-device virtio-blk-pci,drive=d0,x-data-plane=on
ERROR:/home/fam/work/qemu/qom/object.c:1515:
object_get_canonical_path_component: assertion failed: (obj->parent != NULL)
Aborted
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1449485967-19240-1-git-send-email-famz@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
"werror=report" would free the req in virtio_blk_handle_rw_error, we
mustn't write to it in that case.
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1448239280-15025-1-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
When a request R is absorbed by request M, it is appended to the
"mr_next" queue led by M, and is completed together with the completion
of M, in virtio_blk_rw_complete.
During DMA restart in virtio_blk_dma_restart_bh, requests in s->rq are
parsed and submitted again, possibly with a stale req->mr_next. It could
be a problem if the request merging in virtio_blk_handle_request hasn't
refreshed every mr_next pointer, in which case, virtio_blk_rw_complete
could walk through unexpected requests following the stale pointers.
Fix this by unsetting the pointer in virtio_blk_rw_complete. It is safe
because this req is either completed and freed right away, or it will be
restarted and parsed from scratch out of the vq later.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
When creating snapshot with the dataplane enabled, the snapshot file gets
not the actual state of virtqueue, because the current state is stored in
VirtIOBlockDataPlane. Therefore, before saving snapshot need to sync
the dataplane vring state to the virtqueue. The dataplane will resume its
work at the next notify virtqueue.
When snapshot loads with loadvm we get a message:
VQ 0 size 0x80 Guest index 0x15f5 inconsistent with Host index 0x0:
delta 0x15f5
error while loading state for instance 0x0 of device
'0000:00:08.0/virtio-blk'
Error -1 while loading VM state
to reproduce the error I used the following hmp commands:
savevm snap1
loadvm snap1
qemu parameters:
--enable-kvm -smp 4 -m 1024 -drive file=/var/lib/libvirt/images/centos6.4.qcow2,if=none,id=drive-virtio-disk0,format=qcow2,cache=none,aio=native -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,id=virtio-disk0 -set device.virtio-disk0.x-data-plane=on
Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Message-id: 1445859777-2982-1-git-send-email-den@openvz.org
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: "Michael S. Tsirkin" <mst@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Devices that are compliant with virtio-1 do not support scsi
passthrough any more (and it has not been a recommended setup
anyway for quite some time). To avoid having to switch it off
explicitly in newer qemus that turn on virtio-1 by default, let's
switch the default to scsi=false for 2.5.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Message-id: 1444991154-79217-4-git-send-email-cornelia.huck@de.ibm.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Simplify memory allocation by sticking with a single API. GSlice
is not that fast anyway (tcmalloc/jemalloc are better).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The raw-posix block driver implements Linux AIO batching so multiple
requests can be submitted with a single io_submit(2) system call.
Batching is currently only used by virtio-scsi and
virtio-blk-data-plane.
Enable batching for regular virtio-blk so the number of io_submit(2)
system calls is reduced for workloads with queue depth > 1.
In 4KB random read performance tests with queue depth 32, the CPU
utilization on the host is reduced by 9.4%. The fio job is as follows:
[global]
bs=4k
ioengine=libaio
iodepth=32
direct=1
sync=0
time_based=1
runtime=30
clocksource=gettimeofday
ramp_time=5
[job1]
rw=randread
filename=/dev/vdb
size=4096M
write_bw_log=fio
write_iops_log=fio
write_lat_log=fio
log_avg_msec=1000
This benchmark was run on an raw image on LVM. The disk was an SSD
drive and -drive cache=none,aio=native was used.
Tested-by: Pradeep Surisetty <psuriset@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Commit ef546f1275 ("virtio: add
feature checking helpers") introduced a helper __virtio_has_feature.
We don't want to use reserved identifiers, though, so let's
rename __virtio_has_feature to virtio_has_feature and virtio_has_feature
to virtio_vdev_has_feature.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
