Attachment 910820 Details for Bug 1111650 – atlas.disable_error_pragma_decatomic.patch

[patch] atlas.disable_error_pragma_decatomic.patch

atlas.disable_error_pragma_decatomic.patch (text/plain), 1.56 KB, created by Michel Normand on 2014-06-20 16:07:10 UTC

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Creator: Michel Normand

Created: 2014-06-20 16:07:10 UTC

Size: 1.56 KB

patch

obsolete

>Subject: atlas.disable error pragma decatomic
>From: Michel Normand <normand@linux.vnet.ibm.com>
>Date: Fri, 18 Apr 2014 12:08:02 +0200
>
>remove the initial error pragma in ATL_DecAtomicCount_ppc.S
>and handle the guard zone when accessing counter.
>TODO: do I need to save working regs r4, r5 ?
>
>TODO: still draft as build hang in src/threads/ATL_dyntlaunch.c
>as one thread infinit loop at while ... ATL_POLL
>So need more work.
>
>Signed-off-by: Michel Normand <normand@linux.vnet.ibm.com>
>---
> src/threads/ATL_DecAtomicCount_ppc.S |   10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
>Index: ATLAS/src/threads/ATL_DecAtomicCount_ppc.S
>===================================================================
>--- ATLAS.orig/src/threads/ATL_DecAtomicCount_ppc.S
>+++ ATLAS/src/threads/ATL_DecAtomicCount_ppc.S
>@@ -30,13 +30,19 @@ ATL_DecAtomicCount:
>    #endif
>    #endif
> #endif
>+#ifndef __powerpc64__
> #error "Code is not reliable on PPC, don't know why"
>+#endif
> /* r3                           r3  */
> /* int ATL_DecAtomicCount(void *vp) */
>+   li r4,128          /* skip false sharing guard zone */
> RETRY:
>-   lwarx r5, 0, r3    /* Read int from mem, place reservation */
>+   lwarx r5, r4, r3   /* Read int from mem, place reservation */
>    addi  r5, r5, -1   /* decrement value */
>-   stwcx. r5, 0, r3   /* attempt to store decremented value back to mem */
>+   cmpwi r5,0         /* return 0 if count already below 1 */
>+   beq RET
>+   stwcx. r5, r4, r3  /* attempt to store decremented value back to mem */
>    bne-  RETRY        /* If store failed, retry */
>+RET:
>    mr r3, r5
>    blr

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Attachments on bug 1111650: 910819 | 910820