[dpdk-dev] [PATCH 23/28] net/ixgbe: use eal I/O device memory read/write API
Santosh Shukla
santosh.shukla at caviumnetworks.com
Thu Dec 22 13:36:16 CET 2016
Hi Jiangbo,
On Thu, Dec 15, 2016 at 08:40:19PM -0800, Santosh Shukla wrote:
> On Thu, Dec 15, 2016 at 04:37:12PM +0800, Jianbo Liu wrote:
> > On 14 December 2016 at 09:55, Jerin Jacob
> > <jerin.jacob at caviumnetworks.com> wrote:
> > > From: Santosh Shukla <santosh.shukla at caviumnetworks.com>
> > >
> >
> > memory barrier operation is put inside IXGBE_PCI_REG_READ/WRITE in
> > your change, but I found rte_*mb is called before these macros in some
> > places.
> > Can you remove all these redundant calls? And please do the same
> > checking for other drivers.
> >
>
> Ok.
>
> Thinking of adding _relaxed_rd/wr style macro agnostic to arch for ixgbe case
> in particular. Such that for those code incident:
> x86 case> first default barrier + relaxed call.
> arm case> first default barrier + relaxed call.
>
> Does that make sense to you? If so then will take care in v2.
>
> Santosh.
We spend time looking at drivers code where double barrier
may happen. Most of them are in driver init path,
configuration/control path code. So keeping double
barrier won't impact performance.
We plan to replace only fast path code with _relaxed
style API's. That way we won't impact each driver
performance and we'll have the clean port.
Does it make sense? Thought?
>
> > > #define IXGBE_PCI_REG_ADDR(hw, reg) \
> > > ((volatile uint32_t *)((char *)(hw)->hw_addr + (reg)))
> > > --
> > > 2.5.5
> > >
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