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From: "Nicolau, Radu" <radu.nicolau@intel.com>
To: David Marchand <david.marchand@redhat.com>
Cc: dev <dev@dpdk.org>, Beilei Xing <beilei.xing@intel.com>,
	Jeff Guo <jia.guo@intel.com>,
	Bruce Richardson <bruce.richardson@intel.com>,
	"Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	Jerin Jacob <jerinjacobk@gmail.com>
Subject: Re: [dpdk-dev] [PATCH v4 1/2] eal: add WC store functions
Date: Mon, 6 Jul 2020 10:15:01 +0100
Message-ID: <c3ca8034-9b25-be38-8808-269506a545c3@intel.com> (raw)
In-Reply-To: <CAJFAV8wS-pnYk37q6mK7MgVsK3qBre78VWBecpDUKfaBticWOA@mail.gmail.com>

Hi David, thanks for reviewing!

Some comments inline.


On 7/3/2020 4:19 PM, David Marchand wrote:
> On Thu, Jul 2, 2020 at 11:24 AM Radu Nicolau<radu.nicolau@intel.com>  wrote:
>> +static inline void
>> +rte_write32_wc(uint32_t value, volatile void *addr);
> This is a new API, and even if inlined, it should be marked experimental.
Will do.
> Is volatile necessary?
Yes, most of these functions will be called on mmio addresses/volatile 
pointers. All other io functions have it.
>
> +static inline void
> +rte_write32_wc_relaxed(uint32_t value, volatile void *addr);
> +
> +
> Double empty line (there are some other in this patch that I won't flag again).
I will check all occurrences.
>
>
>>   #endif /* __DOXYGEN__ */
>>
>>   #ifndef RTE_OVERRIDE_IO_H
>> @@ -345,6 +378,20 @@ rte_write64(uint64_t value, volatile void *addr)
>>          rte_write64_relaxed(value, addr);
>>   }
>>
>> +#ifndef RTE_NATIVE_WRITE32_WC
> Missing return type, this causes build failure on anything but x86.
Yes, got lost in the copy/paste. I will fix it in the next version
>
>
>> +rte_write32_wc(uint32_t value, volatile void *addr)
>> +{
>> +       rte_write32(value, addr);
>> +}
>> +
>> +static __rte_always_inline void
>> +rte_write32_wc_relaxed(uint32_t value, volatile void *addr)
>> +{
>> +       rte_write32_relaxed(value, addr);
>> +}
>> +#endif /* RTE_NATIVE_WRITE32_WC */
>> +
>> +
>>   #endif /* RTE_OVERRIDE_IO_H */
>>
>>   #endif /* _RTE_IO_H_ */
>> diff --git a/lib/librte_eal/x86/include/rte_io.h b/lib/librte_eal/x86/include/rte_io.h
>> index 2db71b1..c95ed67 100644
>> --- a/lib/librte_eal/x86/include/rte_io.h
>> +++ b/lib/librte_eal/x86/include/rte_io.h
>> @@ -9,8 +9,64 @@
>>   extern "C" {
>>   #endif
>>
>> +#include "rte_cpuflags.h"
> Inclusion of this header should be out of the extern "C" block.
Why? It is used elsewhere inside the extern "C" block e.g. 
x86/rte_spinlock.h
>
>
>> +
>> +#define RTE_NATIVE_WRITE32_WC
>>   #include "generic/rte_io.h"
>>
>> +/**
>> + * @internal
>> + * MOVDIRI wrapper.
>> + */
>> +static __rte_always_inline void
>> +_rte_x86_movdiri(uint32_t value, volatile void *addr)
>> +{
>> +       asm volatile(
>> +               /* MOVDIRI */
>> +               ".byte 0x40, 0x0f, 0x38, 0xf9, 0x02"
>> +               :
>> +               : "a" (value), "d" (addr));
>> +}
>> +
>> +static __rte_always_inline void
>> +rte_write32_wc(uint32_t value, volatile void *addr)
>> +{
>> +       static int _x86_movdiri_flag = -1;
>> +       if (_x86_movdiri_flag == 1) {
>> +               rte_wmb();
>> +               _rte_x86_movdiri(value, addr);
>> +       } else if (_x86_movdiri_flag == 0) {
>> +               rte_write32(value, addr);
>> +       } else {
>> +               _x86_movdiri_flag =
>> +                       (rte_cpu_get_flag_enabled(RTE_CPUFLAG_MOVDIRI) > 0);
> Can't this cpu flag check be moved in a constructor?
> This would avoid this copy/paste.
We evaluated this approach but it creates more problems than if fixes - 
it will need a variable that needs to be exported and there is no good 
place to put it.
>
>
>> +               if (_x86_movdiri_flag == 1) {
>> +                       rte_wmb();
>> +                       _rte_x86_movdiri(value, addr);
>> +               } else {
>> +                       rte_write32(value, addr);
>> +               }
>> +       }
>> +}
>> +
>> +static __rte_always_inline void
>> +rte_write32_wc_relaxed(uint32_t value, volatile void *addr)
>> +{
>> +       static int _x86_movdiri_flag = -1;
> Same check with a static variable with the same name.
It should be no problem, they are static local variables.
>
>
> I wonder if wrapping all of this in a single function would be more elegant.
> Then rte_write32_wc(|_relaxed) would call it with a flag.
Yes, it will be more elegant but also it will cost more, it was written 
like this to minimize the number of branches taken for the movdiri path.

  reply	other threads:[~2020-07-06  9:15 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-11 10:11 [dpdk-dev] [PATCH v1 1/2] eal/x86: add WC store function Radu Nicolau
2020-06-11 10:11 ` [dpdk-dev] [PATCH v1 2/2] net/i40e: use movdiri to update queue tail registers Radu Nicolau
2020-06-11 12:23 ` [dpdk-dev] [PATCH v1 1/2] eal/x86: add WC store function Jerin Jacob
2020-06-11 13:56   ` Nicolau, Radu
2020-06-11 15:33     ` Jerin Jacob
2020-06-15 11:11 ` Ananyev, Konstantin
2020-06-19 12:06 ` [dpdk-dev] [PATCH v2 1/2] eal: add WC store functions Radu Nicolau
2020-06-19 12:06   ` [dpdk-dev] [PATCH v2 2/2] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-01 13:15     ` Bruce Richardson
2020-07-01 13:14   ` [dpdk-dev] [PATCH v2 1/2] eal: add WC store functions Bruce Richardson
2020-07-01 14:15 ` [dpdk-dev] [PATCH v3 0/2] " Radu Nicolau
2020-07-01 14:15   ` [dpdk-dev] [PATCH v3 1/2] " Radu Nicolau
2020-07-01 14:15   ` [dpdk-dev] [PATCH v3 2/2] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-02  9:23 ` [dpdk-dev] [PATCH v4 0/2] eal: add WC store functions Radu Nicolau
2020-07-02  9:23   ` [dpdk-dev] [PATCH v4 1/2] " Radu Nicolau
2020-07-03 15:19     ` David Marchand
2020-07-06  9:15       ` Nicolau, Radu [this message]
2020-07-02  9:23   ` [dpdk-dev] [PATCH v4 2/2] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-06 12:29 ` [dpdk-dev] [PATCH v5 0/2] eal: add WC store functions Radu Nicolau
2020-07-06 12:29   ` [dpdk-dev] [PATCH v5 1/2] " Radu Nicolau
2020-07-06 12:30   ` [dpdk-dev] [PATCH v5 2/2] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-13 12:27 ` [dpdk-dev] [PATCH v6 0/4] eal: add WC store functions Radu Nicolau
2020-07-13 12:27   ` [dpdk-dev] [PATCH v6 1/4] " Radu Nicolau
2020-07-13 12:27   ` [dpdk-dev] [PATCH v6 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-13 12:27   ` [dpdk-dev] [PATCH v6 3/4] qat: " Radu Nicolau
2020-07-13 12:44     ` Bruce Richardson
2020-07-13 12:52       ` Trahe, Fiona
2020-07-13 12:57         ` Bruce Richardson
2020-07-13 12:27   ` [dpdk-dev] [PATCH v6 4/4] net/ixgbe: use WC store to update doorbell register Radu Nicolau
2020-07-16 12:29 ` [dpdk-dev] [PATCH v7 0/4] eal: add WC store functions Radu Nicolau
2020-07-16 12:29   ` [dpdk-dev] [PATCH v7 1/4] " Radu Nicolau
2020-07-16 12:29   ` [dpdk-dev] [PATCH v7 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-16 12:29   ` [dpdk-dev] [PATCH v7 3/4] common/qat: " Radu Nicolau
2020-07-16 12:29   ` [dpdk-dev] [PATCH v7 4/4] net/ixgbe: use WC store to update doorbell register Radu Nicolau
2020-07-17 10:49 ` [dpdk-dev] [PATCH v8 0/4] eal: add WC store functions Radu Nicolau
2020-07-17 10:49   ` [dpdk-dev] [PATCH v8 1/4] " Radu Nicolau
2020-07-20  6:42     ` Ruifeng Wang
2020-07-20  8:52       ` Nicolau, Radu
2020-07-17 10:49   ` [dpdk-dev] [PATCH v8 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-20  6:46     ` Ruifeng Wang
2020-07-20  8:54       ` Nicolau, Radu
2020-07-17 10:49   ` [dpdk-dev] [PATCH v8 3/4] common/qat: " Radu Nicolau
2020-07-17 16:42     ` Trahe, Fiona
2020-07-17 10:49   ` [dpdk-dev] [PATCH v8 4/4] net/ixgbe: " Radu Nicolau
2020-07-17 11:18     ` Ananyev, Konstantin
2020-07-20  9:12 ` [dpdk-dev] [PATCH v9 0/4] eal: add WC store functions Radu Nicolau
2020-07-20  9:12   ` [dpdk-dev] [PATCH v9 1/4] " Radu Nicolau
2020-07-20 12:20     ` David Marchand
2020-07-21  8:56       ` Nicolau, Radu
2020-07-20  9:12   ` [dpdk-dev] [PATCH v9 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-20  9:12   ` [dpdk-dev] [PATCH v9 3/4] common/qat: " Radu Nicolau
2020-07-20  9:12   ` [dpdk-dev] [PATCH v9 4/4] net/ixgbe: " Radu Nicolau
2020-07-21 11:31 ` [dpdk-dev] [PATCH v10 0/4] eal: add WC store functions Radu Nicolau
2020-07-21 11:31   ` [dpdk-dev] [PATCH v10 1/4] " Radu Nicolau
2020-07-21 11:31   ` [dpdk-dev] [PATCH v10 2/4] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-07-21 11:31   ` [dpdk-dev] [PATCH v10 3/4] common/qat: " Radu Nicolau
2020-07-21 11:31   ` [dpdk-dev] [PATCH v10 4/4] net/ixgbe: " Radu Nicolau
2020-08-26  9:55 ` [dpdk-dev] [PATCH v11 0/5] eal: add WC store functions Radu Nicolau
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 1/5] " Radu Nicolau
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 2/5] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-09-23  1:19     ` Lu, Wenzhuo
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 3/5] common/qat: " Radu Nicolau
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 4/5] net/ixgbe: " Radu Nicolau
2020-09-23  1:20     ` Lu, Wenzhuo
2020-08-26  9:55   ` [dpdk-dev] [PATCH v11 5/5] net/ice: " Radu Nicolau
2020-09-23  1:20     ` Lu, Wenzhuo
2020-09-23 14:22 ` [dpdk-dev] [PATCH v12 0/5] eal: add WC store functions Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 1/5] " Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 2/5] net/i40e: use WC store to update queue tail registers Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 3/5] common/qat: " Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 4/5] net/ixgbe: " Radu Nicolau
2020-09-23 14:22   ` [dpdk-dev] [PATCH v12 5/5] net/ice: " Radu Nicolau
2020-10-08  7:28   ` [dpdk-dev] [PATCH v12 0/5] eal: add WC store functions David Marchand
2020-10-08  9:51     ` Nicolau, Radu
2020-10-13  8:57     ` Ferruh Yigit
2020-10-13 12:50   ` David Marchand

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