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Re: [PATCH] S/390: Port of lock elision to System/z
- From: Peter Bergner <bergner at vnet dot ibm dot com>
- To: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Thu, 24 Apr 2014 16:55:41 -0500
- Subject: Re: [PATCH] S/390: Port of lock elision to System/z
- Authentication-results: sourceware.org; auth=none
- References: <ljb7sd$ukp$1 at ger dot gmane dot org> <535979FD dot 9060407 at linux dot vnet dot ibm dot com>
On Thu, 2014-04-24 at 17:54 -0300, Adhemerval Zanella wrote:
> On 24-04-2014 11:42, Stefan Liebler wrote:
> > + else
> > + {
> > + asm volatile ("" ::: "f0", "f1", "f2", "f3", "f4", "f5", "f6",
> > + "f7", "f8", "f9", "f10", "f11", "f12", "f13",
> > + "f14", "f15", "cc", "memory");
>
> Just curious: why do you need this asm assembly? Some arch specific memory barrier?
Unlike on Power, the S390 HTM doesn't rollback any changes to the FP
registers that were made in the failed transaction, so they have to
marked as clobbered.
Peter