Displaying 5 results from an estimated 5 matches for "xchng".
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xchg
2015 Dec 17
4
[PATCH] virtio_ring: use smp_store_mb
...ong barriers/non smp.
It's tempting to use this in vhost as well, for that, we'll
need a variant of smp_store_mb that works on __user pointers.
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
Seems to give a speedup on my box but I'm less sure about this one. E.g. as
xchng faster than mfence on all/most intel CPUs? Anyone has an opinion?
include/linux/virtio_ring.h | 14 ++++++++++++++
drivers/virtio/virtio_ring.c | 15 +++++++++------
2 files changed, 23 insertions(+), 6 deletions(-)
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index 01...
2015 Dec 17
4
[PATCH] virtio_ring: use smp_store_mb
...ong barriers/non smp.
It's tempting to use this in vhost as well, for that, we'll
need a variant of smp_store_mb that works on __user pointers.
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
Seems to give a speedup on my box but I'm less sure about this one. E.g. as
xchng faster than mfence on all/most intel CPUs? Anyone has an opinion?
include/linux/virtio_ring.h | 14 ++++++++++++++
drivers/virtio/virtio_ring.c | 15 +++++++++------
2 files changed, 23 insertions(+), 6 deletions(-)
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index 01...
2015 Dec 17
0
[PATCH] virtio_ring: use smp_store_mb
On Thu, Dec 17, 2015 at 12:32:53PM +0200, Michael S. Tsirkin wrote:
> Seems to give a speedup on my box but I'm less sure about this one. E.g. as
> xchng faster than mfence on all/most intel CPUs? Anyone has an opinion?
Would help if you Cc people who would actually know this :-)
Yes, we've recently established that xchg is indeed faster than mfence
on at least recent machines, see:
lkml.kernel.org/r/CA+55aFynbkeuUGs9s-q+fLY6MeRBA6MjEyWWbbe...
2015 Dec 17
2
[PATCH] virtio_ring: use smp_store_mb
On Thu, Dec 17, 2015 at 12:22:22PM +0100, Peter Zijlstra wrote:
> On Thu, Dec 17, 2015 at 12:32:53PM +0200, Michael S. Tsirkin wrote:
> > Seems to give a speedup on my box but I'm less sure about this one. E.g. as
> > xchng faster than mfence on all/most intel CPUs? Anyone has an opinion?
>
> Would help if you Cc people who would actually know this :-)
Good point. Glad you still saw this. Thanks!
> Yes, we've recently established that xchg is indeed faster than mfence
> on at least recent machines,...
2015 Dec 17
2
[PATCH] virtio_ring: use smp_store_mb
On Thu, Dec 17, 2015 at 12:22:22PM +0100, Peter Zijlstra wrote:
> On Thu, Dec 17, 2015 at 12:32:53PM +0200, Michael S. Tsirkin wrote:
> > Seems to give a speedup on my box but I'm less sure about this one. E.g. as
> > xchng faster than mfence on all/most intel CPUs? Anyone has an opinion?
>
> Would help if you Cc people who would actually know this :-)
Good point. Glad you still saw this. Thanks!
> Yes, we've recently established that xchg is indeed faster than mfence
> on at least recent machines,...