Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Pankaj Suryawanshi <pankaj.suryawanshi@einfochips.com>
To:     "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     "minchan@kernel.org" <minchan@kernel.org>,
        Michal Hocko <mhocko@kernel.org>
Subject: High Latency of CMA allocation
Thread-Topic: High Latency of CMA allocation
Thread-Index: AQHU2xLZ1UQoU59DckqzS9+63pBkgg==
Date:   Fri, 15 Mar 2019 09:49:26 +0000
Message-ID: <SG2PR02MB30984EA8472065757E5F32F7E8440@SG2PR02MB3098.apcprd02.prod.outlook.com>
Accept-Language: en-GB, en-US
Content-Language: en-GB
received-spf: None (protection.outlook.com: einfochips.com does not designate
 permitted sender hosts)
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: af77d70b-5fd2-4baf-58bf-08d6a92b831e
X-MS-Exchange-CrossTenant-originalarrivaltime: 15 Mar 2019 09:49:26.5514
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 0adb040b-ca22-4ca6-9447-ab7b049a22ff
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SG2PR02MB4171
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hello,

I am facing issue of high latency in CMA allocation of large size buffer .

I am frequently allocating/deallocation CMA memory, but latency of allocati=
on is very high.

Below are the stat for allocation/deallocation latency issue.

(389120 kB),  latency 29997 us
(389120 kB),  latency 22957 us
(389120 kB),  latency 25735 us
(389120 kB),  latency 12736 us
(389120 kB),  latency 26009 us
(389120 kB),  latency 18058 us
(389120 kB),  latency 27997 us
(16 kB),  latency 560 us
(256 kB),  latency 280 us
(4 kB), latency 311 us

Is there any workaround or solution for this(cma_alloc latency) issue ?

Regards,
Pankaj
***************************************************************************=
***************************************************************************=
******* eInfochips Business Disclaimer: This e-mail message and all attachm=
ents transmitted with it are intended solely for the use of the addressee a=
nd may contain legally privileged and confidential information. If the read=
er of this message is not the intended recipient, or an employee or agent r=
esponsible for delivering this message to the intended recipient, you are h=
ereby notified that any dissemination, distribution, copying, or other use =
of this message or its attachments is strictly prohibited. If you have rece=
ived this message in error, please notify the sender immediately by replyin=
g to this message and please delete it from your computer. Any views expres=
sed in this message are those of the individual sender unless otherwise sta=
ted. Company has taken enough precautions to prevent the spread of viruses.=
 However the company accepts no liability for any damage caused by any viru=
s transmitted by this email. **********************************************=
***************************************************************************=
************************************