From: Andrii Anisov <andrii.anisov@gmail.com>
To: Julien Grall <julien.grall@gmail.com>
Cc: Julien Grall <julien.grall@arm.com>,
Stefano Stabellini <sstabellini@kernel.org>,
xen-devel@lists.xen.org, "LOPEZ,
FUENTES NACARINO Jairo Eduardo" <jairo@ruri.waseda.jp>,
Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: RT Xen on ARM - R-Car series
Date: Thu, 14 Feb 2019 16:18:54 +0200 [thread overview]
Message-ID: <fee642a7-9a1a-53f1-b0a3-6f47ec0b15cc@gmail.com> (raw)
In-Reply-To: <CAF3u54DiExsh-wPt-oZV-Gh56AvaLLes3PrvZDAHOxpHBLROQg@mail.gmail.com>
Hello Julien,
On 12.02.19 21:21, Julien Grall wrote:
> Please provide more meaningful arguments other than "I don't like it". I provided potential drawbacks on my previous e-mails that you haven't yet addressed.
Well, currently, on each runstate update, `copy_to_guest()` which translates the buffer virtual address is called three times. On context switch, runstate update is done twice, when we change a vcpu.
> FWIW, Volodymyr had the same argument on OP-TEE and I requested to avoid the global mapping. I haven't seen any concern for performance devredation afterwards. Please feel free to come with numbers here.
The numbers here are controversial and really confusing to me.
I've measured the raw `update_runstate_area()` execution time. With runstate mapped - its execution time is less than my timer tick (120ns), with runstate not mapped - I've seen its execution time as 4 to 8 ticks (480-960ns).
But using TBM, I encountered that making runstate mapped with Roger's patch increases the IRQ latency from ~7000ns to ~7900ns. It is opposite to my expectations and to the raw decrease of `runstate_update_area()` execution time.
Also glmark2 benchmark shown me slight performance drop on getting runstate mapping.
--
Sincerely,
Andrii Anisov.
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next prev parent reply other threads:[~2019-02-14 14:18 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CACrvCsaeHuwzZzUQTzNYF7fqmgQWNJUVOQZv9D0MnYrXjqzZtQ@mail.gmail.com>
2018-12-22 12:21 ` RT Xen on ARM - R-Car series Andrii Anisov
2018-12-25 16:07 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2018-12-27 11:07 ` Andrii Anisov
2018-12-28 15:22 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2018-12-28 8:28 ` Andrii Anisov
2018-12-28 8:32 ` Andrii Anisov
2018-12-28 8:39 ` Andrii Anisov
2019-01-04 9:09 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-08 17:04 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-11 20:12 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-14 8:42 ` Andrii Anisov
2019-01-16 7:53 ` Andrii Anisov
2019-01-21 18:04 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
[not found] ` <CACrvCsZB-tps6=Vr=1Phf5oo5eUReabMLJzkbO3d2hmNLDOxww@mail.gmail.com>
[not found] ` <7e217489-2c1a-c35f-d51f-0969654aa8cc@gmail.com>
[not found] ` <CACrvCsaYJ-zGkZwfdV7BXDABW8u_EDQetU3pq+2otRGXWTXagw@mail.gmail.com>
[not found] ` <4d078801-b804-06e7-ad5c-8032b1dbaa84@gmail.com>
2019-01-28 17:20 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-28 8:25 ` Andrii Anisov
2019-01-29 15:30 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-29 13:29 ` Andrii Anisov
2019-01-30 20:23 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2019-01-30 12:12 ` Julien Grall
2019-01-31 11:22 ` Andrii Anisov
2019-01-31 11:37 ` Julien Grall
2019-01-31 12:00 ` Andrii Anisov
2019-01-31 12:20 ` Julien Grall
2019-01-31 21:56 ` Stefano Stabellini
2019-01-31 23:14 ` Julien Grall
2019-02-01 10:02 ` Andrii Anisov
2019-02-01 10:12 ` Julien Grall
2019-02-01 10:35 ` Andrii Anisov
2019-02-01 11:06 ` Julien Grall
2019-02-01 16:53 ` Roger Pau Monné
2019-02-01 17:40 ` Julien Grall
2019-02-04 10:28 ` Andrii Anisov
2019-02-04 11:21 ` Julien Grall
2019-02-04 14:46 ` Andrii Anisov
2019-02-04 15:05 ` Julien Grall
2019-02-04 12:53 ` Roger Pau Monné
2019-02-04 21:58 ` Julien Grall
2019-02-05 8:40 ` Andrii Anisov
2019-02-05 9:45 ` Roger Pau Monné
2019-02-05 9:54 ` Andrii Anisov
2019-02-05 10:10 ` Roger Pau Monné
2019-02-06 20:20 ` Andrii Anisov
2019-02-06 21:03 ` Stefano Stabellini
2019-02-07 9:42 ` Andrii Anisov
2019-02-07 10:35 ` Roger Pau Monné
2019-02-07 10:59 ` Julien Grall
2019-02-12 18:21 ` Andrii Anisov
2019-02-12 19:21 ` Julien Grall
2019-02-14 14:18 ` Andrii Anisov [this message]
2019-02-14 17:29 ` Julien Grall
2019-02-15 11:30 ` Andrii Anisov
2019-02-15 17:13 ` Julien Grall
2019-02-15 17:41 ` Andrii Anisov
2019-02-16 8:42 ` Julien Grall
2019-02-12 18:21 ` Andrii Anisov
2019-02-14 16:29 ` Roger Pau Monné
2019-02-15 15:21 ` Andrii Anisov
2019-02-15 16:31 ` Julien Grall
2019-02-15 17:30 ` Andrii Anisov
2019-02-15 18:36 ` Julien Grall
2019-02-14 17:08 ` Julien Grall
2019-02-05 9:26 ` Roger Pau Monné
2019-02-01 10:07 ` Andrii Anisov
2019-02-01 10:16 ` Julien Grall
2019-02-01 10:35 ` Andrii Anisov
2019-02-01 10:51 ` Julien Grall
2019-02-01 18:00 ` Stefano Stabellini
2019-02-04 10:32 ` Andrii Anisov
2019-02-04 11:36 ` Julien Grall
2019-02-04 15:19 ` Andrii Anisov
2019-02-04 22:06 ` Julien Grall
2019-02-05 9:01 ` Andrii Anisov
2019-02-05 19:18 ` Stefano Stabellini
2019-02-07 10:53 ` Andrii Anisov
[not found] ` <CACrvCsbkFG=3To83qi7xxmtmgC_9PKvuLz73edhiaV7TsJAZqQ@mail.gmail.com>
2019-01-31 12:24 ` Julien Grall
2019-01-16 20:46 ` Andrii Anisov
2019-01-16 7:40 ` Andrii Anisov
2019-01-17 2:08 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
2018-12-28 17:35 ` LOPEZ, FUENTES NACARINO Jairo Eduardo
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