From: Peter Hurley <peter@hurleysoftware.com>
To: Vineet Gupta <Vineet.Gupta1@synopsys.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"robh@kernel.org" <robh@kernel.org>,
"jslaby@suse.cz" <jslaby@suse.cz>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v2 2/3] serial: 8250_early: prepare for dynamic BASE_BAUD
Date: Mon, 05 Jan 2015 09:05:41 -0500 [thread overview]
Message-ID: <54AA9A35.2000806@hurleysoftware.com> (raw)
In-Reply-To: <C2D7FE5348E1B147BCA15975FBA2307565BC9D66@IN01WEMBXA.internal.synopsys.com>
On 01/05/2015 08:52 AM, Vineet Gupta wrote:
> On Monday 05 January 2015 07:04 PM, Peter Hurley wrote:
>>> Also what do u think of the early IER optimization ?
>> Seems ok except the commit changelog is wrong: IER is disabled twice per _line_.
>> How did you profile it? It's ok if the answer is "seemed faster"; I'm just
>> curious.
>
> Looking at the code yes this would be per line - but I vaguely remember seeing it
> for every char - this was when debugging a systemC model for 8250. Its been a while...
> I'd added prints in the model whenever IER would wiggle and it was just being
> written with 0's again and again when in the early polling based printing mode.
Maybe that was while running kgdb through serial8250_put_poll_char(), which is
per-char.
Regards,
Peter Hurley
next prev parent reply other threads:[~2015-01-05 14:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-05 11:30 [PATCH v2 0/3] Early 8250 fixlets Vineet Gupta
2015-01-05 11:30 ` [PATCH v2 1/3] serial: 8250_early: optimize early 8250 uart Vineet Gupta
2015-01-05 11:30 ` [PATCH v2 2/3] serial: 8250_early: prepare for dynamic BASE_BAUD Vineet Gupta
2015-01-05 13:00 ` Peter Hurley
2015-01-05 13:21 ` Vineet Gupta
2015-01-05 13:33 ` Peter Hurley
2015-01-05 13:52 ` Vineet Gupta
2015-01-05 14:05 ` Peter Hurley [this message]
2015-01-05 11:30 ` [PATCH v2 3/3] ARC: runtime determine BASE_BAUD per machine Vineet Gupta
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