| Message ID | 35233df0-3406-e66f-d9d2-bf7ed7814386@huawei.com |
|---|---|
| State | New |
| Headers | show |
On 13/03/17 12:03, Ding Tianhong wrote: > The ARCH_WANT_RELAX_ORDER will enable Relaxed Ordering (RO) which allows > transactions that do not have any order of completion requirements to > complete more efficiently compare to the Stricted Ordering (SO) for ixbge > nic card. Which ixgbe NIC? As far as I can see we have an arch-level config option here which applies to one single driver, and doesn't even cover all the hardware supported by that driver (82598, for example, still has the #ifndef CONFIG_SPARC in the equivalent place). Looking at the history, I'd prefer to at least know what the "various issues with certain chipsets" were, and why they wouldn't affect ARM systems, before making any judgement about whether this could be considered universally safe for arm64. > The system will see high write-to-memory performance when RO is > enabled on the data transactions just like the SPARC did. > > The aarch64 pcie controller could both support Relaxed Ordering (RO) What is "the AArch64 PCIe controller", exactly? Disregarding that talking of PCIe in terms of the CPU ISA makes little sense, I can barely name two ARMv8-based systems which nominally use the same PCIe IP, and the amount of various quirks and incompatibilities I'm aware of leaves me with the default assumption that any such unqualified blanket statement is probably wrong. I think we need some much more considered reasoning here. > and Stricted Ordering (SO), so enable ARCH_WANT_RELAX_ORDER for ixgbe > nic card to get much more better performance, and didn't see any > adverse effects. > > Nic Card(Ixgbe) Disable RO | Enable RO > Performance(Per thread) 8.4Gb/s | 9.4Gb/s > > Tested by Iperf on Hip06/Hip07 Soc Board. > > Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> > --- > arch/arm64/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 8c7c244..36249a3 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -115,6 +115,7 @@ config ARM64 > select SPARSE_IRQ > select SYSCTL_EXCEPTION_TRACE > select THREAD_INFO_IN_TASK > + select ARCH_WANT_RELAX_ORDER I'd say the first order of business is to rename this config option to IXBGE_82599_WANT_RELAXED_ORDER so that it's not entirely misleading and ambiguous. At first glance it looks far more like something scary to do with memory barriers than a network driver option. Howcome this isn't just in drivers/net/intel/Kconfig as a "default y if SPARC" bool anyway? Robin. > help > ARM 64-bit (AArch64) Linux support. >
Hi Robin： On 2017/3/13 21:31, Robin Murphy wrote: > On 13/03/17 12:03, Ding Tianhong wrote: >> The ARCH_WANT_RELAX_ORDER will enable Relaxed Ordering (RO) which allows >> transactions that do not have any order of completion requirements to >> complete more efficiently compare to the Stricted Ordering (SO) for ixbge >> nic card. > > Which ixgbe NIC? As far as I can see we have an arch-level config option > here which applies to one single driver, and doesn't even cover all the > hardware supported by that driver (82598, for example, still has the > #ifndef CONFIG_SPARC in the equivalent place). Looking at the history, > I'd prefer to at least know what the "various issues with certain > chipsets" were, and why they wouldn't affect ARM systems, before making > any judgement about whether this could be considered universally safe > for arm64. > Indeed, in fact if the chipsets didn't support RO mode or has some errata for RO mode, it may occur some issues, but it looks no such aarch64 chips, maybe I miss something. There are several intel nic card could support enable relax order, so need another patch to rename the SPARC to ARCH_WANT_RELAX_ORDER, the universal name looks more better. >> The system will see high write-to-memory performance when RO is >> enabled on the data transactions just like the SPARC did. >> >> The aarch64 pcie controller could both support Relaxed Ordering (RO) > > What is "the AArch64 PCIe controller", exactly? Disregarding that > talking of PCIe in terms of the CPU ISA makes little sense, I can barely > name two ARMv8-based systems which nominally use the same PCIe IP, and > the amount of various quirks and incompatibilities I'm aware of leaves > me with the default assumption that any such unqualified blanket > statement is probably wrong. I think we need some much more considered > reasoning here. > Agree, till now I could only test on hip06/hip07 board and get the better performance, maybe I could test on other aarch64 platform. >> and Stricted Ordering (SO), so enable ARCH_WANT_RELAX_ORDER for ixgbe >> nic card to get much more better performance, and didn't see any >> adverse effects. >> >> Nic Card(Ixgbe) Disable RO | Enable RO >> Performance(Per thread) 8.4Gb/s | 9.4Gb/s >> >> Tested by Iperf on Hip06/Hip07 Soc Board. >> >> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> >> --- >> arch/arm64/Kconfig | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index 8c7c244..36249a3 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -115,6 +115,7 @@ config ARM64 >> select SPARSE_IRQ >> select SYSCTL_EXCEPTION_TRACE >> select THREAD_INFO_IN_TASK >> + select ARCH_WANT_RELAX_ORDER > > I'd say the first order of business is to rename this config option to > IXBGE_82599_WANT_RELAXED_ORDER so that it's not entirely misleading and not only for 82599, including 82598, 82576.... > ambiguous. At first glance it looks far more like something scary to do > with memory barriers than a network driver option. Howcome this isn't > just in drivers/net/intel/Kconfig as a "default y if SPARC" bool anyway? didn't see any essential differences, and I still need to get some Acked by arm maintainer. > Yes, more memory barriers always affect the performance especially for some architecture not just like sparc, any optimization should be taken seriously especially for aarch64. Thanks. Ding > Robin. > >> help >> ARM 64-bit (AArch64) Linux support. >> > > > . >
On Tue, Mar 14, 2017 at 10:06:48PM +0800, Ding Tianhong wrote: > On 2017/3/13 21:31, Robin Murphy wrote: > > On 13/03/17 12:03, Ding Tianhong wrote: > >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > >> index 8c7c244..36249a3 100644 > >> --- a/arch/arm64/Kconfig > >> +++ b/arch/arm64/Kconfig > >> @@ -115,6 +115,7 @@ config ARM64 > >> select SPARSE_IRQ > >> select SYSCTL_EXCEPTION_TRACE > >> select THREAD_INFO_IN_TASK > >> + select ARCH_WANT_RELAX_ORDER > > > > I'd say the first order of business is to rename this config option to > > IXBGE_82599_WANT_RELAXED_ORDER so that it's not entirely misleading and > > not only for 82599, including 82598, 82576.... > > > ambiguous. At first glance it looks far more like something scary to do > > with memory barriers than a network driver option. Howcome this isn't > > just in drivers/net/intel/Kconfig as a "default y if SPARC" bool anyway? > > didn't see any essential differences, and I still need to get some Acked by arm maintainer. > > > > > Yes, more memory barriers always affect the performance especially for > some architecture not just like sparc, any optimization should be taken seriously > especially for aarch64. If this is a legitimate optimisation to apply (which nobody seems to be sure about), then I'd *much* rather it was handled entirely in the driver and predicated on CONFIG_ARM64. I can't select ARCH_WANT_RELAX_ORDER without some notion of what on Earth that means, and whether or not other drivers can also use that to infer some property about the arm64 ordering model. Will
On 14/03/17 14:06, Ding Tianhong wrote: > Hi Robin： > > On 2017/3/13 21:31, Robin Murphy wrote: >> On 13/03/17 12:03, Ding Tianhong wrote: >>> The ARCH_WANT_RELAX_ORDER will enable Relaxed Ordering (RO) which allows >>> transactions that do not have any order of completion requirements to >>> complete more efficiently compare to the Stricted Ordering (SO) for ixbge >>> nic card. >> >> Which ixgbe NIC? As far as I can see we have an arch-level config option >> here which applies to one single driver, and doesn't even cover all the >> hardware supported by that driver (82598, for example, still has the >> #ifndef CONFIG_SPARC in the equivalent place). Looking at the history, >> I'd prefer to at least know what the "various issues with certain >> chipsets" were, and why they wouldn't affect ARM systems, before making >> any judgement about whether this could be considered universally safe >> for arm64. >> > > Indeed, in fact if the chipsets didn't support RO mode or has some errata for RO mode, it may > occur some issues, but it looks no such aarch64 chips, maybe I miss something. > > There are several intel nic card could support enable relax order, so need another patch to rename the SPARC > to ARCH_WANT_RELAX_ORDER, the universal name looks more better. I'm sure I'm not alone in disagreeing outright that it looks better, because ARCH_ is hardly the appropriate namespace for a driver option unrelated to an architecture port's interaction with core kernel code; plus it's further confounded by a name which both doesn't imply any relationship with said driver, and does overlap with the kind of CPU memory model terminology which *is* the purview of architecture ports. As an equivalent example, consider how equally misleading it would be from the ARM maintainer perspective if CONFIG_IOMMU_IO_PGTABLE_LPAE was just called CONFIG_ARCH_WANT_LPAE and implemented in this manner. Having looked into it, I see that "Relaxed Order" does actually turn out to be a specific PCIe term, but even in that context it doesn't apply at the arch level - that's going to be a matter for particular endpoints and particular host controllers and all the quirks in between. >>> The system will see high write-to-memory performance when RO is >>> enabled on the data transactions just like the SPARC did. >>> >>> The aarch64 pcie controller could both support Relaxed Ordering (RO) >> >> What is "the AArch64 PCIe controller", exactly? Disregarding that >> talking of PCIe in terms of the CPU ISA makes little sense, I can barely >> name two ARMv8-based systems which nominally use the same PCIe IP, and >> the amount of various quirks and incompatibilities I'm aware of leaves >> me with the default assumption that any such unqualified blanket >> statement is probably wrong. I think we need some much more considered >> reasoning here. >> > > Agree, till now I could only test on hip06/hip07 board and get the better performance, > maybe I could test on other aarch64 platform. > >>> and Stricted Ordering (SO), so enable ARCH_WANT_RELAX_ORDER for ixgbe >>> nic card to get much more better performance, and didn't see any >>> adverse effects. >>> >>> Nic Card(Ixgbe) Disable RO | Enable RO >>> Performance(Per thread) 8.4Gb/s | 9.4Gb/s >>> >>> Tested by Iperf on Hip06/Hip07 Soc Board. >>> >>> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> >>> --- >>> arch/arm64/Kconfig | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >>> index 8c7c244..36249a3 100644 >>> --- a/arch/arm64/Kconfig >>> +++ b/arch/arm64/Kconfig >>> @@ -115,6 +115,7 @@ config ARM64 >>> select SPARSE_IRQ >>> select SYSCTL_EXCEPTION_TRACE >>> select THREAD_INFO_IN_TASK >>> + select ARCH_WANT_RELAX_ORDER >> >> I'd say the first order of business is to rename this config option to >> IXBGE_82599_WANT_RELAXED_ORDER so that it's not entirely misleading and > > not only for 82599, including 82598, 82576.... So why does ixgbe_start_hw_82598() still have the original #ifndef CONFIG_SPARC from 887012e80aea? It was pretty clear from the outset that this is one of those patches for making a particular card go faster in a particular system based on what's available in the test lab - there's nothing inherently wrong with that, but if it were presented merely in those terms there would probably be a lot less to object to. >> ambiguous. At first glance it looks far more like something scary to do >> with memory barriers than a network driver option. Howcome this isn't >> just in drivers/net/intel/Kconfig as a "default y if SPARC" bool anyway? > > didn't see any essential differences, and I still need to get some Acked by arm maintainer. The big difference is that had people done the sensible thing by adding, say, CONFIG_IXGBE_ALLOW_RELAXED_ORDER to drivers/net/intel/... and sending a self-contained patch through the net tree, architecture maintainers wouldn't even need to be aware, let alone ack anything. Then in future if someone sends another patch against the net tree changing "y if (SPARC || ARM64)" back to "y if SPARC" because it happens to break on their system, the resulting discussion and resolution can happen on netdev, and architecture maintainers who aren't necessarily familiar with particular ixgbe/PCIe hardware details *still* don't need to care. Robin.
On 2017/3/20 22:00, Robin Murphy wrote: > On 14/03/17 14:06, Ding Tianhong wrote: >> Hi Robin： >> >> On 2017/3/13 21:31, Robin Murphy wrote: >>> On 13/03/17 12:03, Ding Tianhong wrote: >>>> The ARCH_WANT_RELAX_ORDER will enable Relaxed Ordering (RO) which allows >>>> transactions that do not have any order of completion requirements to >>>> complete more efficiently compare to the Stricted Ordering (SO) for ixbge >>>> nic card. >>> >>> Which ixgbe NIC? As far as I can see we have an arch-level config option >>> here which applies to one single driver, and doesn't even cover all the >>> hardware supported by that driver (82598, for example, still has the >>> #ifndef CONFIG_SPARC in the equivalent place). Looking at the history, >>> I'd prefer to at least know what the "various issues with certain >>> chipsets" were, and why they wouldn't affect ARM systems, before making >>> any judgement about whether this could be considered universally safe >>> for arm64. >>> >> >> Indeed, in fact if the chipsets didn't support RO mode or has some errata for RO mode, it may >> occur some issues, but it looks no such aarch64 chips, maybe I miss something. >> >> There are several intel nic card could support enable relax order, so need another patch to rename the SPARC >> to ARCH_WANT_RELAX_ORDER, the universal name looks more better. > > I'm sure I'm not alone in disagreeing outright that it looks better, > because ARCH_ is hardly the appropriate namespace for a driver option > unrelated to an architecture port's interaction with core kernel code; > plus it's further confounded by a name which both doesn't imply any > relationship with said driver, and does overlap with the kind of CPU > memory model terminology which *is* the purview of architecture ports. > > As an equivalent example, consider how equally misleading it would be > from the ARM maintainer perspective if CONFIG_IOMMU_IO_PGTABLE_LPAE was > just called CONFIG_ARCH_WANT_LPAE and implemented in this manner. > > Having looked into it, I see that "Relaxed Order" does actually turn out > to be a specific PCIe term, but even in that context it doesn't apply at > the arch level - that's going to be a matter for particular endpoints > and particular host controllers and all the quirks in between. > >>>> The system will see high write-to-memory performance when RO is >>>> enabled on the data transactions just like the SPARC did. >>>> >>>> The aarch64 pcie controller could both support Relaxed Ordering (RO) >>> >>> What is "the AArch64 PCIe controller", exactly? Disregarding that >>> talking of PCIe in terms of the CPU ISA makes little sense, I can barely >>> name two ARMv8-based systems which nominally use the same PCIe IP, and >>> the amount of various quirks and incompatibilities I'm aware of leaves >>> me with the default assumption that any such unqualified blanket >>> statement is probably wrong. I think we need some much more considered >>> reasoning here. >>> >> >> Agree, till now I could only test on hip06/hip07 board and get the better performance, >> maybe I could test on other aarch64 platform. >> >>>> and Stricted Ordering (SO), so enable ARCH_WANT_RELAX_ORDER for ixgbe >>>> nic card to get much more better performance, and didn't see any >>>> adverse effects. >>>> >>>> Nic Card(Ixgbe) Disable RO | Enable RO >>>> Performance(Per thread) 8.4Gb/s | 9.4Gb/s >>>> >>>> Tested by Iperf on Hip06/Hip07 Soc Board. >>>> >>>> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> >>>> --- >>>> arch/arm64/Kconfig | 1 + >>>> 1 file changed, 1 insertion(+) >>>> >>>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >>>> index 8c7c244..36249a3 100644 >>>> --- a/arch/arm64/Kconfig >>>> +++ b/arch/arm64/Kconfig >>>> @@ -115,6 +115,7 @@ config ARM64 >>>> select SPARSE_IRQ >>>> select SYSCTL_EXCEPTION_TRACE >>>> select THREAD_INFO_IN_TASK >>>> + select ARCH_WANT_RELAX_ORDER >>> >>> I'd say the first order of business is to rename this config option to >>> IXBGE_82599_WANT_RELAXED_ORDER so that it's not entirely misleading and >> >> not only for 82599, including 82598, 82576.... > > So why does ixgbe_start_hw_82598() still have the original #ifndef > CONFIG_SPARC from 887012e80aea? > > It was pretty clear from the outset that this is one of those patches > for making a particular card go faster in a particular system based on > what's available in the test lab - there's nothing inherently wrong with > that, but if it were presented merely in those terms there would > probably be a lot less to object to. > >>> ambiguous. At first glance it looks far more like something scary to do >>> with memory barriers than a network driver option. Howcome this isn't >>> just in drivers/net/intel/Kconfig as a "default y if SPARC" bool anyway? >> >> didn't see any essential differences, and I still need to get some Acked by arm maintainer. > > The big difference is that had people done the sensible thing by adding, > say, CONFIG_IXGBE_ALLOW_RELAXED_ORDER to drivers/net/intel/... and > sending a self-contained patch through the net tree, architecture > maintainers wouldn't even need to be aware, let alone ack anything. Then > in future if someone sends another patch against the net tree changing > "y if (SPARC || ARM64)" back to "y if SPARC" because it happens to break > on their system, the resulting discussion and resolution can happen on > netdev, and architecture maintainers who aren't necessarily familiar > with particular ixgbe/PCIe hardware details *still* don't need to care. > > Robin. > Ok, after a period of thinking and verification, I believe it is not only affect for hisilicon, and will try to find a better way to fix this according to your opinions, thanks. Ding > . >
Hi Robin and all > -----Original Message----- > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel- > owner@vger.kernel.org] On Behalf Of Robin Murphy > Sent: 20 March 2017 14:00 > To: Dingtianhong; Catalin Marinas; Will Deacon; linux-arm- > kernel@lists.infradead.org; linux-kernel@vger.kernel.org > Cc: alexander.duyck@gmail.com; maowenan > Subject: Re: [PATCH] arm64: enable ARCH_WANT_RELAX_ORDER for aarch64 > > On 14/03/17 14:06, Ding Tianhong wrote: > > Hi Robin： > > > > On 2017/3/13 21:31, Robin Murphy wrote: > >> On 13/03/17 12:03, Ding Tianhong wrote: > >>> The ARCH_WANT_RELAX_ORDER will enable Relaxed Ordering (RO) which > allows > >>> transactions that do not have any order of completion requirements > to > >>> complete more efficiently compare to the Stricted Ordering (SO) for > ixbge > >>> nic card. > >> > >> Which ixgbe NIC? As far as I can see we have an arch-level config > option > >> here which applies to one single driver, and doesn't even cover all > the > >> hardware supported by that driver (82598, for example, still has the > >> #ifndef CONFIG_SPARC in the equivalent place). Looking at the > history, > >> I'd prefer to at least know what the "various issues with certain > >> chipsets" were, and why they wouldn't affect ARM systems, before > making > >> any judgement about whether this could be considered universally > safe > >> for arm64. > >> > > > > Indeed, in fact if the chipsets didn't support RO mode or has some > errata for RO mode, it may > > occur some issues, but it looks no such aarch64 chips, maybe I miss > something. > > > > There are several intel nic card could support enable relax order, so > need another patch to rename the SPARC > > to ARCH_WANT_RELAX_ORDER, the universal name looks more better. > > I'm sure I'm not alone in disagreeing outright that it looks better, > because ARCH_ is hardly the appropriate namespace for a driver option > unrelated to an architecture port's interaction with core kernel code; > plus it's further confounded by a name which both doesn't imply any > relationship with said driver, and does overlap with the kind of CPU > memory model terminology which *is* the purview of architecture ports. > > As an equivalent example, consider how equally misleading it would be > from the ARM maintainer perspective if CONFIG_IOMMU_IO_PGTABLE_LPAE was > just called CONFIG_ARCH_WANT_LPAE and implemented in this manner. > > Having looked into it, I see that "Relaxed Order" does actually turn > out > to be a specific PCIe term, but even in that context it doesn't apply > at > the arch level - that's going to be a matter for particular endpoints > and particular host controllers and all the quirks in between. I fully agree on this and to be honest I don't understand how <<commit 1a8b6d76dc5b "net:add one common config ARCH_WANT_RELAX_ORDER to support relax ordering">> has landed into mainline... > > >>> The system will see high write-to-memory performance when RO is > >>> enabled on the data transactions just like the SPARC did. > >>> > >>> The aarch64 pcie controller could both support Relaxed Ordering > (RO) > >> > >> What is "the AArch64 PCIe controller", exactly? Disregarding that > >> talking of PCIe in terms of the CPU ISA makes little sense, I can > barely > >> name two ARMv8-based systems which nominally use the same PCIe IP, > and > >> the amount of various quirks and incompatibilities I'm aware of > leaves > >> me with the default assumption that any such unqualified blanket > >> statement is probably wrong. I think we need some much more > considered > >> reasoning here. > >> > > > > Agree, till now I could only test on hip06/hip07 board and get the > better performance, > > maybe I could test on other aarch64 platform. > > > >>> and Stricted Ordering (SO), so enable ARCH_WANT_RELAX_ORDER for > ixgbe > >>> nic card to get much more better performance, and didn't see any > >>> adverse effects. > >>> > >>> Nic Card(Ixgbe) Disable RO | Enable RO > >>> Performance(Per thread) 8.4Gb/s | 9.4Gb/s > >>> > >>> Tested by Iperf on Hip06/Hip07 Soc Board. > >>> > >>> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> > >>> --- > >>> arch/arm64/Kconfig | 1 + > >>> 1 file changed, 1 insertion(+) > >>> > >>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > >>> index 8c7c244..36249a3 100644 > >>> --- a/arch/arm64/Kconfig > >>> +++ b/arch/arm64/Kconfig > >>> @@ -115,6 +115,7 @@ config ARM64 > >>> select SPARSE_IRQ > >>> select SYSCTL_EXCEPTION_TRACE > >>> select THREAD_INFO_IN_TASK > >>> + select ARCH_WANT_RELAX_ORDER > >> > >> I'd say the first order of business is to rename this config option > to > >> IXBGE_82599_WANT_RELAXED_ORDER so that it's not entirely misleading > and > > > > not only for 82599, including 82598, 82576.... > > So why does ixgbe_start_hw_82598() still have the original #ifndef > CONFIG_SPARC from 887012e80aea? > > It was pretty clear from the outset that this is one of those patches > for making a particular card go faster in a particular system based on > what's available in the test lab - there's nothing inherently wrong > with > that, but if it were presented merely in those terms there would > probably be a lot less to object to. > > >> ambiguous. At first glance it looks far more like something scary to > do > >> with memory barriers than a network driver option. Howcome this > isn't > >> just in drivers/net/intel/Kconfig as a "default y if SPARC" bool > anyway? > > > > didn't see any essential differences, and I still need to get some > Acked by arm maintainer. > > The big difference is that had people done the sensible thing by > adding, > say, CONFIG_IXGBE_ALLOW_RELAXED_ORDER to drivers/net/intel/... and > sending a self-contained patch through the net tree, architecture > maintainers wouldn't even need to be aware, let alone ack anything. > Then > in future if someone sends another patch against the net tree changing > "y if (SPARC || ARM64)" back to "y if SPARC" because it happens to > break > on their system, the resulting discussion and resolution can happen on > netdev, and architecture maintainers who aren't necessarily familiar > with particular ixgbe/PCIe hardware details *still* don't need to care. Standard PCIe drivers uses bit 4 of the Device Control Register to enable/disable relaxed ordering: here it is not clear what Intel means by relaxed ordering and in which context (at least not to me) and why it should be disabled by default. From my perspective I would try to propose the following patch as RFC and see what the Intel maintainer comes up with and if any other ARM64 host vendor would oppose to it. The RFC below reverts commit 1a8b6d76dc5b and enable relaxed ordering on SPARC and ARM64 machines... What do you think? > > Robin.diff --git a/arch/Kconfig b/arch/Kconfig index cd211a1..e03d354 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -844,7 +844,4 @@ config STRICT_MODULE_RWX and non-text memory will be made non-executable. This provides protection against certain security exploits (e.g. writing to text) -config ARCH_WANT_RELAX_ORDER - bool - source "kernel/gcov/Kconfig" diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 68ac5c7..cf4034c 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -44,7 +44,6 @@ config SPARC select CPU_NO_EFFICIENT_FFS select HAVE_ARCH_HARDENED_USERCOPY select PROVE_LOCKING_SMALL if PROVE_LOCKING - select ARCH_WANT_RELAX_ORDER config SPARC32 def_bool !64BIT diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c index c38d50c..d55dcac 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c @@ -350,7 +350,8 @@ s32 ixgbe_start_hw_gen2(struct ixgbe_hw *hw) } IXGBE_WRITE_FLUSH(hw); -#ifndef CONFIG_ARCH_WANT_RELAX_ORDER +#if !defined(CONFIG_SPARC) && !defined(CONFIG_ARM64) + /* Disable relaxed ordering */ for (i = 0; i < hw->mac.max_tx_queues; i++) { u32 regval;
On 2017/4/7 23:57, Gabriele Paoloni wrote: > Hi Robin and all > >> -----Original Message----- >> From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel- >> owner@vger.kernel.org] On Behalf Of Robin Murphy >> Sent: 20 March 2017 14:00 >> To: Dingtianhong; Catalin Marinas; Will Deacon; linux-arm- >> kernel@lists.infradead.org; linux-kernel@vger.kernel.org >> Cc: alexander.duyck@gmail.com; maowenan >> Subject: Re: [PATCH] arm64: enable ARCH_WANT_RELAX_ORDER for aarch64 >> >> On 14/03/17 14:06, Ding Tianhong wrote: >>> Hi Robin： >>> >>> On 2017/3/13 21:31, Robin Murphy wrote: >>>> On 13/03/17 12:03, Ding Tianhong wrote: >>>>> The ARCH_WANT_RELAX_ORDER will enable Relaxed Ordering (RO) which >> allows >>>>> transactions that do not have any order of completion requirements >> to >>>>> complete more efficiently compare to the Stricted Ordering (SO) for >> ixbge >>>>> nic card. >>>> >>>> Which ixgbe NIC? As far as I can see we have an arch-level config >> option >>>> here which applies to one single driver, and doesn't even cover all >> the >>>> hardware supported by that driver (82598, for example, still has the >>>> #ifndef CONFIG_SPARC in the equivalent place). Looking at the >> history, >>>> I'd prefer to at least know what the "various issues with certain >>>> chipsets" were, and why they wouldn't affect ARM systems, before >> making >>>> any judgement about whether this could be considered universally >> safe >>>> for arm64. >>>> >>> >>> Indeed, in fact if the chipsets didn't support RO mode or has some >> errata for RO mode, it may >>> occur some issues, but it looks no such aarch64 chips, maybe I miss >> something. >>> >>> There are several intel nic card could support enable relax order, so >> need another patch to rename the SPARC >>> to ARCH_WANT_RELAX_ORDER, the universal name looks more better. >> >> I'm sure I'm not alone in disagreeing outright that it looks better, >> because ARCH_ is hardly the appropriate namespace for a driver option >> unrelated to an architecture port's interaction with core kernel code; >> plus it's further confounded by a name which both doesn't imply any >> relationship with said driver, and does overlap with the kind of CPU >> memory model terminology which *is* the purview of architecture ports. >> >> As an equivalent example, consider how equally misleading it would be >> from the ARM maintainer perspective if CONFIG_IOMMU_IO_PGTABLE_LPAE was >> just called CONFIG_ARCH_WANT_LPAE and implemented in this manner. >> >> Having looked into it, I see that "Relaxed Order" does actually turn >> out >> to be a specific PCIe term, but even in that context it doesn't apply >> at >> the arch level - that's going to be a matter for particular endpoints >> and particular host controllers and all the quirks in between. > > I fully agree on this and to be honest I don't understand how > <<commit 1a8b6d76dc5b "net:add one common config ARCH_WANT_RELAX_ORDER > to support relax ordering">> has landed into mainline... > > >> >>>>> The system will see high write-to-memory performance when RO is >>>>> enabled on the data transactions just like the SPARC did. >>>>> >>>>> The aarch64 pcie controller could both support Relaxed Ordering >> (RO) >>>> >>>> What is "the AArch64 PCIe controller", exactly? Disregarding that >>>> talking of PCIe in terms of the CPU ISA makes little sense, I can >> barely >>>> name two ARMv8-based systems which nominally use the same PCIe IP, >> and >>>> the amount of various quirks and incompatibilities I'm aware of >> leaves >>>> me with the default assumption that any such unqualified blanket >>>> statement is probably wrong. I think we need some much more >> considered >>>> reasoning here. >>>> >>> >>> Agree, till now I could only test on hip06/hip07 board and get the >> better performance, >>> maybe I could test on other aarch64 platform. >>> >>>>> and Stricted Ordering (SO), so enable ARCH_WANT_RELAX_ORDER for >> ixgbe >>>>> nic card to get much more better performance, and didn't see any >>>>> adverse effects. >>>>> >>>>> Nic Card(Ixgbe) Disable RO | Enable RO >>>>> Performance(Per thread) 8.4Gb/s | 9.4Gb/s >>>>> >>>>> Tested by Iperf on Hip06/Hip07 Soc Board. >>>>> >>>>> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> >>>>> --- >>>>> arch/arm64/Kconfig | 1 + >>>>> 1 file changed, 1 insertion(+) >>>>> >>>>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >>>>> index 8c7c244..36249a3 100644 >>>>> --- a/arch/arm64/Kconfig >>>>> +++ b/arch/arm64/Kconfig >>>>> @@ -115,6 +115,7 @@ config ARM64 >>>>> select SPARSE_IRQ >>>>> select SYSCTL_EXCEPTION_TRACE >>>>> select THREAD_INFO_IN_TASK >>>>> + select ARCH_WANT_RELAX_ORDER >>>> >>>> I'd say the first order of business is to rename this config option >> to >>>> IXBGE_82599_WANT_RELAXED_ORDER so that it's not entirely misleading >> and >>> >>> not only for 82599, including 82598, 82576.... >> >> So why does ixgbe_start_hw_82598() still have the original #ifndef >> CONFIG_SPARC from 887012e80aea? >> >> It was pretty clear from the outset that this is one of those patches >> for making a particular card go faster in a particular system based on >> what's available in the test lab - there's nothing inherently wrong >> with >> that, but if it were presented merely in those terms there would >> probably be a lot less to object to. >> >>>> ambiguous. At first glance it looks far more like something scary to >> do >>>> with memory barriers than a network driver option. Howcome this >> isn't >>>> just in drivers/net/intel/Kconfig as a "default y if SPARC" bool >> anyway? >>> >>> didn't see any essential differences, and I still need to get some >> Acked by arm maintainer. >> >> The big difference is that had people done the sensible thing by >> adding, >> say, CONFIG_IXGBE_ALLOW_RELAXED_ORDER to drivers/net/intel/... and >> sending a self-contained patch through the net tree, architecture >> maintainers wouldn't even need to be aware, let alone ack anything. >> Then >> in future if someone sends another patch against the net tree changing >> "y if (SPARC || ARM64)" back to "y if SPARC" because it happens to >> break >> on their system, the resulting discussion and resolution can happen on >> netdev, and architecture maintainers who aren't necessarily familiar >> with particular ixgbe/PCIe hardware details *still* don't need to care. > > Standard PCIe drivers uses bit 4 of the Device Control Register to > enable/disable relaxed ordering: here it is not clear what Intel means > by relaxed ordering and in which context (at least not to me) and why > it should be disabled by default. > > From my perspective I would try to propose the following patch as RFC > and see what the Intel maintainer comes up with and if any other ARM64 > host vendor would oppose to it. > The RFC below reverts commit 1a8b6d76dc5b and enable relaxed ordering > on SPARC and ARM64 machines... > > What do you think? > Hi Gab: Till now I didn't get any useful feedback from the latest version patches, it is really hard to unify everyone's opinion, I will follow your solution and send a new version patch, thanks. Ding > > diff --git a/arch/Kconfig b/arch/Kconfig > index cd211a1..e03d354 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -844,7 +844,4 @@ config STRICT_MODULE_RWX > and non-text memory will be made non-executable. This provides > protection against certain security exploits (e.g. writing to text) > > -config ARCH_WANT_RELAX_ORDER > - bool > - > source "kernel/gcov/Kconfig" > diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig > index 68ac5c7..cf4034c 100644 > --- a/arch/sparc/Kconfig > +++ b/arch/sparc/Kconfig > @@ -44,7 +44,6 @@ config SPARC > select CPU_NO_EFFICIENT_FFS > select HAVE_ARCH_HARDENED_USERCOPY > select PROVE_LOCKING_SMALL if PROVE_LOCKING > - select ARCH_WANT_RELAX_ORDER > > config SPARC32 > def_bool !64BIT > diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c > index c38d50c..d55dcac 100644 > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c > @@ -350,7 +350,8 @@ s32 ixgbe_start_hw_gen2(struct ixgbe_hw *hw) > } > IXGBE_WRITE_FLUSH(hw); > > -#ifndef CONFIG_ARCH_WANT_RELAX_ORDER > +#if !defined(CONFIG_SPARC) && !defined(CONFIG_ARM64) > + > /* Disable relaxed ordering */ > for (i = 0; i < hw->mac.max_tx_queues; i++) { > u32 regval; > > >> >> Robin.
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 8c7c244..36249a3 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -115,6 +115,7 @@ config ARM64 select SPARSE_IRQ select SYSCTL_EXCEPTION_TRACE select THREAD_INFO_IN_TASK + select ARCH_WANT_RELAX_ORDER help ARM 64-bit (AArch64) Linux support.
The ARCH_WANT_RELAX_ORDER will enable Relaxed Ordering (RO) which allows transactions that do not have any order of completion requirements to complete more efficiently compare to the Stricted Ordering (SO) for ixbge nic card. The system will see high write-to-memory performance when RO is enabled on the data transactions just like the SPARC did. The aarch64 pcie controller could both support Relaxed Ordering (RO) and Stricted Ordering (SO), so enable ARCH_WANT_RELAX_ORDER for ixgbe nic card to get much more better performance, and didn't see any adverse effects. Nic Card(Ixgbe) Disable RO | Enable RO Performance(Per thread) 8.4Gb/s | 9.4Gb/s Tested by Iperf on Hip06/Hip07 Soc Board. Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+) -- 1.9.0