From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: "Yang, Zhiyong" <zhiyong.yang@intel.com>,
Thomas Monjalon <thomas.monjalon@6wind.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"yuanhan.liu@linux.intel.com" <yuanhan.liu@linux.intel.com>,
"Richardson, Bruce" <bruce.richardson@intel.com>,
"De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
Subject: Re: [dpdk-dev] [PATCH 1/4] eal/common: introduce rte_memset on IA platform
Date: Thu, 15 Dec 2016 10:53:40 +0000 [thread overview]
Message-ID: <2601191342CEEE43887BDE71AB9772583F0EFF66@irsmsx105.ger.corp.intel.com> (raw)
In-Reply-To: <E182254E98A5DA4EB1E657AC7CB9BD2A3EB599D4@BGSMSX101.gar.corp.intel.com>
Hi Zhiyong,
> -----Original Message-----
> From: Yang, Zhiyong
> Sent: Thursday, December 15, 2016 6:51 AM
> To: Yang, Zhiyong <zhiyong.yang@intel.com>; Ananyev, Konstantin <konstantin.ananyev@intel.com>; Thomas Monjalon
> <thomas.monjalon@6wind.com>
> Cc: dev@dpdk.org; yuanhan.liu@linux.intel.com; Richardson, Bruce <bruce.richardson@intel.com>; De Lara Guarch, Pablo
> <pablo.de.lara.guarch@intel.com>
> Subject: RE: [dpdk-dev] [PATCH 1/4] eal/common: introduce rte_memset on IA platform
>
> Hi, Thomas, Konstantin:
>
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Yang, Zhiyong
> > Sent: Sunday, December 11, 2016 8:33 PM
> > To: Ananyev, Konstantin <konstantin.ananyev@intel.com>; Thomas
> > Monjalon <thomas.monjalon@6wind.com>
> > Cc: dev@dpdk.org; yuanhan.liu@linux.intel.com; Richardson, Bruce
> > <bruce.richardson@intel.com>; De Lara Guarch, Pablo
> > <pablo.de.lara.guarch@intel.com>
> > Subject: Re: [dpdk-dev] [PATCH 1/4] eal/common: introduce rte_memset on
> > IA platform
> >
> > Hi, Konstantin, Bruce:
> >
> > > -----Original Message-----
> > > From: Ananyev, Konstantin
> > > Sent: Thursday, December 8, 2016 6:31 PM
> > > To: Yang, Zhiyong <zhiyong.yang@intel.com>; Thomas Monjalon
> > > <thomas.monjalon@6wind.com>
> > > Cc: dev@dpdk.org; yuanhan.liu@linux.intel.com; Richardson, Bruce
> > > <bruce.richardson@intel.com>; De Lara Guarch, Pablo
> > > <pablo.de.lara.guarch@intel.com>
> > > Subject: RE: [dpdk-dev] [PATCH 1/4] eal/common: introduce rte_memset
> > > on IA platform
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: Yang, Zhiyong
> > > > Sent: Thursday, December 8, 2016 9:53 AM
> > > > To: Ananyev, Konstantin <konstantin.ananyev@intel.com>; Thomas
> > > > Monjalon <thomas.monjalon@6wind.com>
> > > > Cc: dev@dpdk.org; yuanhan.liu@linux.intel.com; Richardson, Bruce
> > > > <bruce.richardson@intel.com>; De Lara Guarch, Pablo
> > > > <pablo.de.lara.guarch@intel.com>
> > > > Subject: RE: [dpdk-dev] [PATCH 1/4] eal/common: introduce rte_memset
> > > > on IA platform
> > > >
> > > extern void *(*__rte_memset_vector)( (void *s, int c, size_t n);
> > >
> > > static inline void*
> > > rte_memset_huge(void *s, int c, size_t n) {
> > > return __rte_memset_vector(s, c, n); }
> > >
> > > static inline void *
> > > rte_memset(void *s, int c, size_t n)
> > > {
> > > If (n < XXX)
> > > return rte_memset_scalar(s, c, n);
> > > else
> > > return rte_memset_huge(s, c, n);
> > > }
> > >
> > > XXX could be either a define, or could also be a variable, so it can
> > > be setuped at startup, depending on the architecture.
> > >
> > > Would that work?
> > > Konstantin
> > >
> I have implemented the code for choosing the functions at run time.
> rte_memcpy is used more frequently, So I test it at run time.
>
> typedef void *(*rte_memcpy_vector_t)(void *dst, const void *src, size_t n);
> extern rte_memcpy_vector_t rte_memcpy_vector;
> static inline void *
> rte_memcpy(void *dst, const void *src, size_t n)
> {
> return rte_memcpy_vector(dst, src, n);
> }
> In order to reduce the overhead at run time,
> I assign the function address to var rte_memcpy_vector before main() starts to init the var.
>
> static void __attribute__((constructor))
> rte_memcpy_init(void)
> {
> if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX2))
> {
> rte_memcpy_vector = rte_memcpy_avx2;
> }
> else if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SSE4_1))
> {
> rte_memcpy_vector = rte_memcpy_sse;
> }
> else
> {
> rte_memcpy_vector = memcpy;
> }
>
> }
I thought we discussed a bit different approach.
In which rte_memcpy_vector() (rte_memeset_vector) would be called only after some cutoff point, i.e:
void
rte_memcpy(void *dst, const void *src, size_t len)
{
if (len < N) memcpy(dst, src, len);
else rte_memcpy_vector(dst, src, len);
}
If you just always call rte_memcpy_vector() for every len,
then it means that compiler most likely has always to generate a proper call
(not inlining happening).
For small length(s) price of extra function would probably overweight any
potential gain with SSE/AVX2 implementation.
Konstantin
> I run the same virtio/vhost loopback tests without NIC.
> I can see the throughput drop when running choosing functions at run time
> compared to original code as following on the same platform(my machine is haswell)
> Packet size perf drop
> 64 -4%
> 256 -5.4%
> 1024 -5%
> 1500 -2.5%
> Another thing, I run the memcpy_perf_autotest, when N= <128,
> the rte_memcpy perf gains almost disappears
> When choosing functions at run time. For N=other numbers, the perf gains will become narrow.
>
> Thanks
> Zhiyong
next prev parent reply other threads:[~2016-12-15 10:53 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-05 8:26 [dpdk-dev] [PATCH 0/4] eal/common: introduce rte_memset and related test Zhiyong Yang
2016-12-02 10:00 ` Maxime Coquelin
2016-12-06 6:33 ` Yang, Zhiyong
2016-12-06 8:29 ` Maxime Coquelin
2016-12-07 9:28 ` Yang, Zhiyong
2016-12-07 9:37 ` Yuanhan Liu
2016-12-07 9:43 ` Yang, Zhiyong
2016-12-07 9:48 ` Yuanhan Liu
2016-12-05 8:26 ` [dpdk-dev] [PATCH 1/4] eal/common: introduce rte_memset on IA platform Zhiyong Yang
2016-12-02 10:25 ` Thomas Monjalon
2016-12-08 7:41 ` Yang, Zhiyong
2016-12-08 9:26 ` Ananyev, Konstantin
2016-12-08 9:53 ` Yang, Zhiyong
2016-12-08 10:27 ` Bruce Richardson
2016-12-08 10:30 ` Ananyev, Konstantin
2016-12-11 12:32 ` Yang, Zhiyong
2016-12-15 6:51 ` Yang, Zhiyong
2016-12-15 10:12 ` Bruce Richardson
2016-12-16 10:19 ` Yang, Zhiyong
2016-12-19 6:27 ` Yuanhan Liu
2016-12-20 2:41 ` Yao, Lei A
2016-12-15 10:53 ` Ananyev, Konstantin [this message]
2016-12-16 2:15 ` Yang, Zhiyong
2016-12-16 11:47 ` Ananyev, Konstantin
2016-12-20 9:31 ` Yang, Zhiyong
2016-12-08 15:09 ` Thomas Monjalon
2016-12-11 12:04 ` Yang, Zhiyong
2016-12-27 10:04 ` [dpdk-dev] [PATCH v2 0/4] eal/common: introduce rte_memset and related test Zhiyong Yang
2016-12-27 10:04 ` [dpdk-dev] [PATCH v2 1/4] eal/common: introduce rte_memset on IA platform Zhiyong Yang
2016-12-27 10:04 ` [dpdk-dev] [PATCH v2 2/4] app/test: add functional autotest for rte_memset Zhiyong Yang
2016-12-27 10:04 ` [dpdk-dev] [PATCH v2 3/4] app/test: add performance " Zhiyong Yang
2016-12-27 10:04 ` [dpdk-dev] [PATCH v2 4/4] lib/librte_vhost: improve vhost perf using rte_memset Zhiyong Yang
2017-01-09 9:48 ` [dpdk-dev] [PATCH v2 0/4] eal/common: introduce rte_memset and related test Yang, Zhiyong
2017-01-17 6:24 ` Yang, Zhiyong
2017-01-17 20:14 ` Thomas Monjalon
2017-01-18 0:15 ` Vincent JARDIN
2017-01-18 2:42 ` Yang, Zhiyong
2017-01-18 7:42 ` Thomas Monjalon
2017-01-19 1:36 ` Yang, Zhiyong
2016-12-05 8:26 ` [dpdk-dev] [PATCH 2/4] app/test: add functional autotest for rte_memset Zhiyong Yang
2016-12-05 8:26 ` [dpdk-dev] [PATCH 3/4] app/test: add performance " Zhiyong Yang
2016-12-05 8:26 ` [dpdk-dev] [PATCH 4/4] lib/librte_vhost: improve vhost perf using rte_memset Zhiyong Yang
2016-12-02 9:46 ` Thomas Monjalon
2016-12-06 8:04 ` Yang, Zhiyong
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