The implementation of the current virtio-balloon is not very efficient,
Bellow is test result of time spends on inflating the balloon to 3GB of
a 4GB idle guest:
a. allocating pages (6.5%, 103ms)
b. sending PFNs to host (68.3%, 787ms)
c. address translation (6.1%, 96ms)
d. madvise (19%, 300ms)
It
On 20/05/2016 11:59, Liang Li wrote:
> +
> + sg_init_table(sg, 5);
> + sg_set_buf(&sg[0], &flags, sizeof(flags));
> + sg_set_buf(&sg[1], &start_pfn, sizeof(start_pfn));
> + sg_set_buf(&sg[2], &page_shift, sizeof(page_shift));
> + sg_set_
On Fri, 20 May 2016 17:59:46 +0800
Liang Li wrote:
> The implementation of the current virtio-balloon is not very efficient,
> Bellow is test result of time spends on inflating the balloon to 3GB of
> a 4GB idle guest:
>
> a. allocating pages (6.5%, 103ms)
> b. sending PFNs to host (68.3%, 787ms
On Fri, May 20, 2016 at 05:59:46PM +0800, Liang Li wrote:
> The implementation of the current virtio-balloon is not very efficient,
> Bellow is test result of time spends on inflating the balloon to 3GB of
> a 4GB idle guest:
>
> a. allocating pages (6.5%, 103ms)
> b. sending PFNs to host (68.3%,
> On Fri, 20 May 2016 17:59:46 +0800
> Liang Li wrote:
>
> > The implementation of the current virtio-balloon is not very
> > efficient, Bellow is test result of time spends on inflating the
> > balloon to 3GB of a 4GB idle guest:
> >
> > a. allocating pages (6.5%, 103ms)
> > b. sending PFNs to h
> On 20/05/2016 11:59, Liang Li wrote:
> > +
> > + sg_init_table(sg, 5);
> > + sg_set_buf(&sg[0], &flags, sizeof(flags));
> > + sg_set_buf(&sg[1], &start_pfn, sizeof(start_pfn));
> > + sg_set_buf(&sg[2], &page_shift, sizeof(page_shift));
> > + sg_se
> On Fri, May 20, 2016 at 05:59:46PM +0800, Liang Li wrote:
> > The implementation of the current virtio-balloon is not very
> > efficient, Bellow is test result of time spends on inflating the
> > balloon to 3GB of a 4GB idle guest:
> >
> > a. allocating pages (6.5%, 103ms)
> > b. sending PFNs to
> > On Fri, May 20, 2016 at 05:59:46PM +0800, Liang Li wrote:
> > > The implementation of the current virtio-balloon is not very
> > > efficient, Bellow is test result of time spends on inflating the
> > > balloon to 3GB of a 4GB idle guest:
> > >
> > > a. allocating pages (6.5%, 103ms)
> > > b. se
On Tue, May 24, 2016 at 09:51:46AM +, Li, Liang Z wrote:
> > On Fri, May 20, 2016 at 05:59:46PM +0800, Liang Li wrote:
> > > The implementation of the current virtio-balloon is not very
> > > efficient, Bellow is test result of time spends on inflating the
> > > balloon to 3GB of a 4GB idle gue
> > > > {
> > > > - struct scatterlist sg;
> > > > unsigned int len;
> > > >
> > > > - sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns);
> > > > + if (virtio_has_feature(vb->vdev,
> > > VIRTIO_BALLOON_F_PAGE_BITMAP)) {
> > > > + u32 page_shift
On Tue, May 24, 2016 at 10:38:43AM +, Li, Liang Z wrote:
> > > > > {
> > > > > - struct scatterlist sg;
> > > > > unsigned int len;
> > > > >
> > > > > - sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns);
> > > > > + if (virtio_has_feature(vb->vdev,
> > > > VIRTI
> > > > > This can be pre-initialized, correct?
> > > >
> > > > pre-initialized? I am not quite understand your mean.
> > >
> > > I think you can maintain sg as part of device state and init sg with the
> bitmap.
> > >
> >
> > I got it.
> >
> > > > > This is grossly inefficient if you only requeste
On Tue, May 24, 2016 at 02:36:08PM +, Li, Liang Z wrote:
> > > > > > This can be pre-initialized, correct?
> > > > >
> > > > > pre-initialized? I am not quite understand your mean.
> > > >
> > > > I think you can maintain sg as part of device state and init sg with the
> > bitmap.
> > > >
> > >
> On Tue, May 24, 2016 at 02:36:08PM +, Li, Liang Z wrote:
> > > > > > > This can be pre-initialized, correct?
> > > > > >
> > > > > > pre-initialized? I am not quite understand your mean.
> > > > >
> > > > > I think you can maintain sg as part of device state and init sg
> > > > > with the
> >
> > > > > > > This is grossly inefficient if you only requested a single page.
> > > > > > > And it's also allocating memory very aggressively without
> > > > > > > ever telling the host what is going on.
> > > > > >
> > > > > > If only requested a single page, there is no need to send the
> > > >
On Wed, May 25, 2016 at 01:00:27AM +, Li, Liang Z wrote:
> It should be changed if we are going to use a small page bitmap.
Exactly.
> > > Suggestion to address all above comments:
> > > 1. allocate a bunch of pages and link them up,
> > > calculating the min and the max pfn.
> > > if max-min exceeds the allocated bitmap size,
> > > tell host.
> >
> > I am not sure if it works well in some cases, e.g. The alloca
On Wed, May 25, 2016 at 08:48:17AM +, Li, Liang Z wrote:
> > > > Suggestion to address all above comments:
> > > > 1. allocate a bunch of pages and link them up,
> > > >calculating the min and the max pfn.
> > > >if max-min exceeds the allocated bitmap size,
> >
> On Wed, May 25, 2016 at 08:48:17AM +, Li, Liang Z wrote:
> > > > > Suggestion to address all above comments:
> > > > > 1. allocate a bunch of pages and link them up,
> > > > > calculating the min and the max pfn.
> > > > > if max-min exceeds the allocated bitmap size,
On Wed, May 25, 2016 at 09:28:58AM +, Li, Liang Z wrote:
> > On Wed, May 25, 2016 at 08:48:17AM +, Li, Liang Z wrote:
> > > > > > Suggestion to address all above comments:
> > > > > > 1. allocate a bunch of pages and link them up,
> > > > > >calculating the min and the max pfn.
> > > >
> > > > Hi MST,
> > > >
> > > > I have measured the performance when using a 32K page bitmap,
> > >
> > > Just to make sure. Do you mean a 32Kbyte bitmap?
> > > Covering 1Gbyte of memory?
> > Yes.
> >
> > >
> > > > and inflate the balloon to 3GB
> > > > of an idle guest with 4GB RAM.
> > >
On Wed, May 25, 2016 at 10:10:47AM +, Li, Liang Z wrote:
> > > > >
> > > > > Hi MST,
> > > > >
> > > > > I have measured the performance when using a 32K page bitmap,
> > > >
> > > > Just to make sure. Do you mean a 32Kbyte bitmap?
> > > > Covering 1Gbyte of memory?
> > > Yes.
> > >
> > > >
> >
> > > Interesting. How about instead of tell host, we do multiple scans,
> > > each time ignoring pages out of range?
> > >
> > > for (pfn = min pfn; pfn < max pfn; pfn += 1G) {
> > > foreach page
> > > if page pfn < pfn || page pfn >= pfn + 1G
> > >
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