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From: Stephen Hemminger <stephen@networkplumber.org>
To: Suanming Mou <suanmingm@nvidia.com>
Cc: Ori Kam <orika@mellanox.com>,
	John McNamara <john.mcnamara@intel.com>,
	Marko Kovacevic <marko.kovacevic@intel.com>,
	Matan Azrad <matan@mellanox.com>,
	Shahaf Shuler <shahafs@mellanox.com>,
	"Viacheslav Ovsiienko" <viacheslavo@mellanox.com>,
	NBU-Contact-Thomas Monjalon <thomas@monjalon.net>,
	Ferruh Yigit <ferruh.yigit@intel.com>,
	"Andrew Rybchenko" <arybchenko@solarflare.com>,
	"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [RFC] ethdev: make rte flow API thread safe
Date: Tue, 8 Sep 2020 07:52:08 -0700	[thread overview]
Message-ID: <20200908075208.048bfa02@hermes.lan> (raw)
In-Reply-To: <MN2PR12MB3550EEEB531A0CFCB5EE7293C1280@MN2PR12MB3550.namprd12.prod.outlook.com>

On Mon, 7 Sep 2020 02:36:48 +0000
Suanming Mou <suanmingm@nvidia.com> wrote:

> Hi,
> 
> Sorry for my late reply due to the vacation.
> 
> > What is the performance impact of this for currently working applications that
> > use a single thread to program flow rules.  You are adding a couple of system
> > calls to what was formerly a totally usermode operation.  
> 

Read the source for glibc and see what pthread_mutex does

> If I understand correctly, in the non-contended single thread case, pthread mutex lock should not go to the kernel space.
> I also wrote a small application with pthread mutex, and strace shows no system call was introduced.
> 
> Another simple testing code below is to check the cycles cost difference in every round between pthread mutex and spin_lock.
> 

Micro benchmarks of locking is hard to see.


  reply	other threads:[~2020-09-08 14:52 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-03  4:53 Suanming Mou
2020-09-03 17:37 ` Stephen Hemminger
2020-09-07  2:36   ` Suanming Mou
2020-09-08 14:52     ` Stephen Hemminger [this message]
2020-09-08 15:03       ` Thomas Monjalon
2020-09-08 16:02         ` Stephen Hemminger
2020-09-09  2:26           ` Suanming Mou
2020-09-24  1:42             ` Suanming Mou
2020-09-09  1:26       ` Suanming Mou

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