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From: Peter Korsgaard <jacmet-OfajU3CKLf1/SzgSGea1oA@public.gmane.org>
To: joakim.tjernlund-SNLAxHN9vbcOP4wsBPIw7w@public.gmane.org
Cc: David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>,
	spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: Performance of spi_mpc83xx.c sucks.
Date: Tue, 02 Dec 2008 17:23:42 +0100	[thread overview]
Message-ID: <87d4gav94h.fsf@macbook.be.48ers.dk> (raw)
In-Reply-To: <1228231118.9867.108.camel-/EMGr9iCeazgSi9v3i4K4Pmbkio/vSLMs0AfqQuZ5sE@public.gmane.org> (Joakim Tjernlund's message of "Tue\, 02 Dec 2008 16\:18\:38 +0100")

>>>>> "Joakim" == Joakim Tjernlund <joakim.tjernlund-SNLAxHN9vbcOP4wsBPIw7w@public.gmane.org> writes:

Hi,

 >> So long as you do the polling with IRQs enabled, I'd keep it
 >> simple and just always poll.  YMMV of course, but most devices
 >> seem to prefer more like 10 MHz clocks than 1 MHz ones.

 Joakim> Sorry for the delay, forgot about this.

 Joakim> Won't polling for long periods starve user space? How to
 Joakim> overcome this?

I guess it won't be any worse than the processor being overloaded with
interrupts - In fact it's better, as there's more real work done.

 Joakim> Why use a kernel thread(mpc83xx_spi.0) to do the work?  Would
 Joakim> it not be better if the polling was in process context?

I guess that's needed for the async stuff.

-- 
Bye, Peter Korsgaard

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  parent reply	other threads:[~2008-12-02 16:23 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-21 16:19 Performance of spi_mpc83xx.c sucks Joakim Tjernlund
     [not found] ` <1224605947.14078.17.camel-/EMGr9iCeazgSi9v3i4K4Pmbkio/vSLMs0AfqQuZ5sE@public.gmane.org>
2008-10-21 18:14   ` Peter Korsgaard
     [not found]     ` <877i81rf2g.fsf-uXGAPMMVk8amE9MCos8gUmSdvHPH+/yF@public.gmane.org>
2008-10-21 18:31       ` Joakim Tjernlund
     [not found]     ` <002f01c933ab$4bee9180$e3cbb480$@Tjernlund@transmode.se>
     [not found]       ` <002f01c933ab$4bee9180$e3cbb480$@Tjernlund-SNLAxHN9vbcOP4wsBPIw7w@public.gmane.org>
2008-11-21  4:10         ` David Brownell
     [not found]           ` <200811202010.30845.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-12-02 15:20             ` Joakim Tjernlund
     [not found]               ` <1228231118.9867.108.camel-/EMGr9iCeazgSi9v3i4K4Pmbkio/vSLMs0AfqQuZ5sE@public.gmane.org>
2008-12-02 16:23                 ` Peter Korsgaard [this message]
     [not found]                   ` <87d4gav94h.fsf-uXGAPMMVk8amE9MCos8gUmSdvHPH+/yF@public.gmane.org>
2008-12-02 18:20                     ` Joakim Tjernlund
     [not found]                   ` <040001c954aa$a00e3930$e02aab90$@Tjernlund@transmode.se>
     [not found]                     ` <040001c954aa$a00e3930$e02aab90$@Tjernlund-SNLAxHN9vbcOP4wsBPIw7w@public.gmane.org>
2008-12-02 18:31                       ` David Brownell
     [not found]                         ` <200812021031.26711.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-12-02 18:58                           ` Joakim Tjernlund
     [not found]                         ` <041201c954af$f32ad3d0$d9807b70$@Tjernlund@transmode.se>
     [not found]                           ` <041201c954af$f32ad3d0$d9807b70$@Tjernlund-SNLAxHN9vbcOP4wsBPIw7w@public.gmane.org>
2008-12-02 20:46                             ` David Brownell
     [not found]                               ` <200812021246.27884.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-12-02 22:12                                 ` Joakim Tjernlund
     [not found]                               ` <041e01c954cb$15c0f030$4142d090$@Tjernlund@transmode.se>
     [not found]                                 ` <041e01c954cb$15c0f030$4142d090$@Tjernlund-SNLAxHN9vbcOP4wsBPIw7w@public.gmane.org>
2008-12-03  8:56                                   ` David Brownell
2008-12-02 18:17                 ` David Brownell
     [not found]                   ` <200812021017.11880.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-12-02 18:25                     ` Joakim Tjernlund
     [not found]                   ` <040601c954ab$554cff20$ffe6fd60$@Tjernlund@transmode.se>
     [not found]                     ` <040601c954ab$554cff20$ffe6fd60$@Tjernlund-SNLAxHN9vbcOP4wsBPIw7w@public.gmane.org>
2008-12-02 19:10                       ` David Brownell

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