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From: Manfred Spraul <manfred@colorfullife.com>
To: Alan <alan@lxorguk.ukuu.org.uk>, Zwane Mwaikambo <zwane@holomorphy.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH][2.5] smp_call_function_mask
Date: Tue, 21 Jan 2003 08:13:43 +0100	[thread overview]
Message-ID: <3E2CF327.8030107@colorfullife.com> (raw)

Alan wrote:

>On Fri, 2003-01-17 at 05:18, Zwane Mwaikambo wrote:
>> +	/* Wait for response */
>> +	while (atomic_read(&data.started) != num_cpus)
>> +		barrier();
>
>Only old old intel x86 that does -bad- things as it
>generates a lot of bus locked cycles. Better to do
>
>	while(atomic_read(&data.started) != num_cpus)
>		while(data.started.value != num_cpus)
>		{
>			barrier();
>			cpu_relax();
>		}
>
>I would think ?
>
>  
>
from 2.5.52, <asm-i386/atomic.h>
    #define atomic_read(v)          ((v)->counter)
AFAIK atomic_read never contained locked bus cycles.

Btw, Zwane, what about removing non_atomic from the prototype?

--
    Manfred


             reply	other threads:[~2003-01-21  7:04 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-01-21  7:13 Manfred Spraul [this message]
2003-01-21  8:07 ` [PATCH][2.5] smp_call_function_mask Zwane Mwaikambo
2003-01-21  9:21   ` Zwane Mwaikambo
2003-01-21 17:13     ` Manfred Spraul
2003-01-21 17:49       ` Zwane Mwaikambo
2003-01-21 23:14 ` Alan Cox
  -- strict thread matches above, loose matches on Subject: below --
2003-01-17  5:18 Zwane Mwaikambo
2003-01-17  5:44 ` Andrew Morton
2003-01-17  5:56   ` Zwane Mwaikambo
2003-01-20 23:19 ` Alan
2003-01-21  7:16   ` Zwane Mwaikambo

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