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From: "Phil Yang (Arm Technology China)" <Phil.Yang@arm.com>
To: "Hunt, David" <david.hunt@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"thomas@monjalon.net" <thomas@monjalon.net>
Cc: "reshma.pattan@intel.com" <reshma.pattan@intel.com>,
	"Gavin Hu (Arm Technology China)" <Gavin.Hu@arm.com>,
	Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	nd <nd@arm.com>, nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH v4 2/3] test/distributor: replace sync builtins with atomic builtins
Date: Thu, 11 Apr 2019 11:31:40 +0000	[thread overview]
Message-ID: <DB7PR08MB3385B398972C39D3A99C58A5E92F0@DB7PR08MB3385.eurprd08.prod.outlook.com> (raw)
Message-ID: <20190411113140.hmEzLZRKPfIt8FplNXpCEz4s3Z7joDNeQypRWMUxFSM@z> (raw)
In-Reply-To: <85718290-9c5a-01f5-21ab-0f1000e4dfde@intel.com>

> -----Original Message-----
> From: Hunt, David <david.hunt@intel.com>
> Sent: Wednesday, April 10, 2019 10:06 PM
> To: Phil Yang (Arm Technology China) <Phil.Yang@arm.com>; dev@dpdk.org;
> thomas@monjalon.net
> Cc: reshma.pattan@intel.com; Gavin Hu (Arm Technology China)
> <Gavin.Hu@arm.com>; Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com>; nd <nd@arm.com>
> Subject: Re: [PATCH v4 2/3] test/distributor: replace sync builtins with atomic
> builtins
> 
> Hi Phil,
> 
> On 8/4/2019 4:02 AM, Phil Yang wrote:
> > '__sync' built-in functions are deprecated, should use the '__atomic'
> > built-in instead. the sync built-in functions are full barriers, while
> > atomic built-in functions offer less restrictive one-way barriers,
> > which help performance.
> >
> > Here is the example test result on TX2:
> > sudo ./arm64-armv8a-linuxapp-gcc/app/test -l 112-139 \ -n 4
> > --socket-mem=1024,1024 -- -i
> > RTE>>distributor_perf_autotest
> >
> > *** distributor_perf_autotest without this patch *** ==== Cache line
> > switch test === Time for 33554432 iterations = 1519202730 ticks Ticks
> > per iteration = 45
> >
> > *** distributor_perf_autotest with this patch *** ==== Cache line
> > switch test === Time for 33554432 iterations = 1251715496 ticks Ticks
> > per iteration = 37
> >
> > Less ticks needed for the cache line switch test. It got 17% of
> > performance improvement.
> 
> 
Hi, Dave

Thanks for your input.

> I'm seeing about an 8% performance degradation on my platform for the

I'd tested this patch on our x86 server (E5-2640 v3 @ 2.60GHz) several rounds. However, I didn't found performance degradation. Please check the test result below.
$ sudo  ./x86_64-native-linuxapp-gcc/app/test -l 8-15 -n 4 --socket-mem=1024,1024 -- -i
RTE>>distributor_perf_autotest

####  without this patch ####
==== Cache line switch test ===
Time for 33554432 iterations = 12379399910 ticks
Ticks per iteration = 368

=== Performance test of distributor (single mode) ===
Time per burst:  5815
Time per packet: 90

=== Performance test of distributor (burst mode) ===
Time per burst:  3487
Time per packet: 54

####  with this patch ####
==== Cache line switch test ===
Time for 33554432 iterations = 12388791845 ticks
Ticks per iteration = 369

=== Performance test of distributor (single mode) ===
Time per burst:  5796
Time per packet: 90

=== Performance test of distributor (burst mode) ===
Time per burst:  3477
Time per packet: 54

From my test, there was a little bit of performance improvement (You can also think of it as a measurement bias) on x86. 

> cache line switch test with the patch, however the single mode and burst
> mode tests area showing no difference, which are the more important tests.
> What kind of differences are you seeing in the single/burst mode tests?

Actually, I found no difference in the single mode and burst mode on aarch64 neither. I think it means this test case is not the hotspot for those two mode's performance. 

Just like the __sync_xxx builtins, the __atomic_xxx builtins are atomic operations, which elide the memory barrier. So I think it should benefit all platform.

Thanks,
Phil
> 
> Rgds,
> Dave.
> 
> 
> ---snip---
> 
> 


  parent reply	other threads:[~2019-04-11 11:31 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-03  9:49 [dpdk-dev] [PATCH] packet_ordering: " Phil Yang
2019-03-28 18:42 ` Thomas Monjalon
2019-03-28 18:42   ` Thomas Monjalon
2019-03-29  1:34   ` Phil Yang (Arm Technology China)
2019-03-29  1:34     ` Phil Yang (Arm Technology China)
2019-03-29 10:56 ` [dpdk-dev] [PATCH v2 0/3] example and test cases optimizations Phil Yang
2019-03-29 10:56   ` Phil Yang
2019-03-29 10:56 ` [dpdk-dev] [PATCH v2 1/3] packet_ordering: add statistics for each worker thread Phil Yang
2019-03-29 10:56   ` Phil Yang
2019-03-29 16:39   ` Pattan, Reshma
2019-03-29 16:39     ` Pattan, Reshma
2019-03-30 16:55     ` Phil Yang (Arm Technology China)
2019-03-30 16:55       ` Phil Yang (Arm Technology China)
2019-04-01 12:58       ` Pattan, Reshma
2019-04-01 12:58         ` Pattan, Reshma
2019-04-02  3:33         ` Phil Yang (Arm Technology China)
2019-04-02  3:33           ` Phil Yang (Arm Technology China)
2019-03-29 10:56 ` [dpdk-dev] [PATCH v2 2/3] test/distributor: replace sync builtins with atomic builtins Phil Yang
2019-03-29 10:56   ` Phil Yang
2019-04-01 16:24   ` Honnappa Nagarahalli
2019-04-01 16:24     ` Honnappa Nagarahalli
2019-04-02  3:43     ` Phil Yang (Arm Technology China)
2019-04-02  3:43       ` Phil Yang (Arm Technology China)
2019-03-29 10:56 ` [dpdk-dev] [PATCH v2 3/3] test/ring_perf: " Phil Yang
2019-03-29 10:56   ` Phil Yang
2019-04-01 16:24   ` Honnappa Nagarahalli
2019-04-01 16:24     ` Honnappa Nagarahalli
2019-04-03  6:59 ` [dpdk-dev] [PATCH v3 0/3] example and test cases optimizations Phil Yang
2019-04-03  6:59   ` Phil Yang
2019-04-03  6:59   ` [dpdk-dev] [PATCH v3 1/3] packet_ordering: add statistics for each worker thread Phil Yang
2019-04-03  6:59     ` Phil Yang
2019-04-04 23:24     ` Thomas Monjalon
2019-04-04 23:24       ` Thomas Monjalon
2019-04-08  4:04       ` Phil Yang (Arm Technology China)
2019-04-08  4:04         ` Phil Yang (Arm Technology China)
2019-04-03  6:59   ` [dpdk-dev] [PATCH v3 2/3] test/distributor: replace sync builtins with atomic builtins Phil Yang
2019-04-03  6:59     ` Phil Yang
2019-04-04 15:30     ` Honnappa Nagarahalli
2019-04-04 15:30       ` Honnappa Nagarahalli
2019-04-03  6:59   ` [dpdk-dev] [PATCH v3 3/3] test/ring_perf: " Phil Yang
2019-04-03  6:59     ` Phil Yang
2019-04-08  3:02 ` [dpdk-dev] [PATCH v4 0/3] example and test cases optimizations Phil Yang
2019-04-08  3:02   ` Phil Yang
2019-07-04 20:15   ` Thomas Monjalon
2019-07-05  3:19     ` Phil Yang (Arm Technology China)
2019-07-08 14:38   ` Thomas Monjalon
2019-04-08  3:02 ` [dpdk-dev] [PATCH v4 1/3] packet_ordering: add statistics for each worker thread Phil Yang
2019-04-08  3:02   ` Phil Yang
2019-04-08  3:02 ` [dpdk-dev] [PATCH v4 2/3] test/distributor: replace sync builtins with atomic builtins Phil Yang
2019-04-08  3:02   ` Phil Yang
2019-04-10 14:05   ` Hunt, David
2019-04-10 14:05     ` Hunt, David
2019-04-11 11:31     ` Phil Yang (Arm Technology China) [this message]
2019-04-11 11:31       ` Phil Yang (Arm Technology China)
2019-04-08  3:02 ` [dpdk-dev] [PATCH v4 3/3] test/ring_perf: " Phil Yang
2019-04-08  3:02   ` Phil Yang

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