search for: indirections

Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will use indirect descriptors even if we have plenty of space in the ring. This means that we take a performance hit at all times due to the overhead of creating indirect descriptors. With this patch, we will use indirect descriptors only if we have less than either 16, or 12% of the total amount of descriptors available. I did basic

Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will use indirect descriptors even if we have plenty of space in the ring. This means that we take a performance hit at all times due to the overhead of creating indirect descriptors. With this patch, we will use indirect descriptors only if we have less than either 16, or 12% of the total amount of descriptors available. I did basic

Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/vhost/vhost.c | 93 +++++++++++++++++++++++++++++++-------------------- 1 file changed, 56 insertions(+), 37 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index c90f437..4d379ed 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -33,8 +33,8 @@ enum { VHOST_MEMORY_F_LOG = 0x1, };

Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/vhost/vhost.c | 93 +++++++++++++++++++++++++++++++-------------------- 1 file changed, 56 insertions(+), 37 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index c90f437..4d379ed 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -33,8 +33,8 @@ enum { VHOST_MEMORY_F_LOG = 0x1, };

On Thu, Oct 17, 2019 at 10:17:18AM +0800, Jason Wang wrote: > On 2019/10/17 ??7:33, Will Deacon wrote: > > In an attempt to remove the remaining traces of [smp_]read_barrier_depends() > > following my previous patches to strengthen READ_ONCE() for Alpha [1], I > > ended up trying to decipher the read_barrier_depends() usage in the vhost > > driver: > > > >

On Thu, Oct 17, 2019 at 10:17:18AM +0800, Jason Wang wrote: > On 2019/10/17 ??7:33, Will Deacon wrote: > > In an attempt to remove the remaining traces of [smp_]read_barrier_depends() > > following my previous patches to strengthen READ_ONCE() for Alpha [1], I > > ended up trying to decipher the read_barrier_depends() usage in the vhost > > driver: > > > >

Dave Airlie <airlied at gmail.com> writes: > Hi Rusty, > > current virtio-ring.c has a BUG_ON in virtqueue_add that checks > total_sg > vg->vring.num, however I'm not sure it really is 100% > correct. > > If I have an indirect ring and I'm adding sgs to it and the host is > delayed (say I've got a thread consuming things from the vring and its >

Dave Airlie <airlied at gmail.com> writes: > Hi Rusty, > > current virtio-ring.c has a BUG_ON in virtqueue_add that checks > total_sg > vg->vring.num, however I'm not sure it really is 100% > correct. > > If I have an indirect ring and I'm adding sgs to it and the host is > delayed (say I've got a thread consuming things from the vring and its >

On 2020/6/3 ??5:48, Michael S. Tsirkin wrote: > On Wed, Jun 03, 2020 at 03:13:56PM +0800, Jason Wang wrote: >> On 2020/6/2 ??9:05, Michael S. Tsirkin wrote: [...] >>> + >>> +static int fetch_indirect_descs(struct vhost_virtqueue *vq, >>> + struct vhost_desc *indirect, >>> + u16 head) >>> +{ >>> + struct vring_desc desc;

On Tue, Feb 14, 2023 at 3:27 PM Xuan Zhuo <xuanzhuo at linux.alibaba.com> wrote: > > DMA-related logic is separated from the virtqueue_add_split to prepare > for subsequent support for premapped. The patch seems to do more than what is described here. To simplify reviewers, I'd suggest to split this patch into three: 1) virtqueue_add_split_prepare() (could we have a better

Hi All, We've been working on enhancing LLVM's instrumentation based profiling by adding indirect call target profiling support. Our goal is to add instrumentation around indirect call sites, so that we may track the frequently taken target addresses and their call frequencies. The acquired data has uses in optimization of indirect function call heavy applications. Our initial findings

Add documentation for indirect descriptors Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- virtio-spec.lyx | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 114 insertions(+), 4 deletions(-) diff --git a/virtio-spec.lyx b/virtio-spec.lyx index 8062e11..b5a8fbd 100644 --- a/virtio-spec.lyx +++ b/virtio-spec.lyx @@ -1,4 +1,4 @@ -#LyX 1.6.4 created

Add documentation for indirect descriptors Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- virtio-spec.lyx | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 114 insertions(+), 4 deletions(-) diff --git a/virtio-spec.lyx b/virtio-spec.lyx index 8062e11..b5a8fbd 100644 --- a/virtio-spec.lyx +++ b/virtio-spec.lyx @@ -1,4 +1,4 @@ -#LyX 1.6.4 created

Hi, we've implemented an indirect call promotion llvm pass. The design notes including examples are shown below. This pass complements the indirect call profile infrastructure http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-April/084271.html Your feedback and comments will be highly appreciated. Thanks, Ivan ============================================================================RFC:

This commit splits virtqueue_add_split() to two functions. The purpose of such splitting is to separate DMA operations. The first function includes all codes that may fail before the DMA operation. The subsequent part is used as the second function. In this way, we can perform DMA operations in the middle of the two functions. If the first function fails, we do not need to perform DMA

On Mon, Dec 01, 2014 at 01:33:53PM +0100, Cornelia Huck wrote: > On Sun, 30 Nov 2014 17:11:49 +0200 > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > > --- > > drivers/vhost/vhost.c | 93 +++++++++++++++++++++++++++++++-------------------- > > 1 file changed, 56 insertions(+), 37

On Mon, Dec 01, 2014 at 01:33:53PM +0100, Cornelia Huck wrote: > On Sun, 30 Nov 2014 17:11:49 +0200 > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > > --- > > drivers/vhost/vhost.c | 93 +++++++++++++++++++++++++++++++-------------------- > > 1 file changed, 56 insertions(+), 37

On Thursday 24 July 2008 01:47, Chris Lattner wrote: > On Jul 23, 2008, at 8:47 PM, kapil anand wrote: > > Specifically, I need a way to represent indirect branch instruction > > (in binary) as an equivalent LLVM instruction. With switch > > instruction , I would have to list all the possible targets and then > > initialize the corresponding instruction. I was just

On 2020/6/2 ??9:05, Michael S. Tsirkin wrote: > The idea is to support multiple ring formats by converting > to a format-independent array of descriptors. > > This costs extra cycles, but we gain in ability > to fetch a batch of descriptors in one go, which > is good for code cache locality. > > When used, this causes a minor performance degradation, > it's been kept

On 2020/6/2 ??9:05, Michael S. Tsirkin wrote: > The idea is to support multiple ring formats by converting > to a format-independent array of descriptors. > > This costs extra cycles, but we gain in ability > to fetch a batch of descriptors in one go, which > is good for code cache locality. > > When used, this causes a minor performance degradation, > it's been kept