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Date: Mon, 27 Feb 2012 08:11:40 +0000
From: "Jan Beulich" <JBeulich@suse.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: <mingo@elte.hu>, <tglx@linutronix.de>, <ak@linux.intel.com>,
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Subject: Re: [PATCH, resend] x86-64: improve insn scheduling in
 SAVE_ARGS_IRQ
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>>> On 24.02.12 at 21:21, "H. Peter Anvin" <hpa@zytor.com> wrote:
> On 02/24/2012 03:55 AM, Jan Beulich wrote:
>>  	leaq -RBP(%rsp),%rdi	/* arg1 for handler */
>> -	testl $3, CS(%rdi)
>> +	testl $3, CS-RBP(%rsi)
>>  	je 1f
> 
> IIRC there is no imm8 version of testl; could this be a testb instead or
> is that going to cause stalls on some platforms you think?

As far as I'm aware, memory operations don't suffer "partial register
stalls" or alike, so yes, using a testb here ought to be appropriate.

Jan