diff options
-rw-r--r-- | arch/ia64/include/asm/io.h | 24 |
1 files changed, 0 insertions, 24 deletions
diff --git a/arch/ia64/include/asm/io.h b/arch/ia64/include/asm/io.h index 7f257507cd86..0d9d16e2d949 100644 --- a/arch/ia64/include/asm/io.h +++ b/arch/ia64/include/asm/io.h | |||
@@ -434,28 +434,4 @@ extern void memset_io(volatile void __iomem *s, int c, long n); | |||
434 | 434 | ||
435 | # endif /* __KERNEL__ */ | 435 | # endif /* __KERNEL__ */ |
436 | 436 | ||
437 | /* | ||
438 | * Enabling BIO_VMERGE_BOUNDARY forces us to turn off I/O MMU bypassing. It is said that | ||
439 | * BIO-level virtual merging can give up to 4% performance boost (not verified for ia64). | ||
440 | * On the other hand, we know that I/O MMU bypassing gives ~8% performance improvement on | ||
441 | * SPECweb-like workloads on zx1-based machines. Thus, for now we favor I/O MMU bypassing | ||
442 | * over BIO-level virtual merging. | ||
443 | */ | ||
444 | extern unsigned long ia64_max_iommu_merge_mask; | ||
445 | #if 1 | ||
446 | #define BIO_VMERGE_BOUNDARY 0 | ||
447 | #else | ||
448 | /* | ||
449 | * It makes no sense at all to have this BIO_VMERGE_BOUNDARY macro here. Should be | ||
450 | * replaced by dma_merge_mask() or something of that sort. Note: the only way | ||
451 | * BIO_VMERGE_BOUNDARY is used is to mask off bits. Effectively, our definition gets | ||
452 | * expanded into: | ||
453 | * | ||
454 | * addr & ((ia64_max_iommu_merge_mask + 1) - 1) == (addr & ia64_max_iommu_vmerge_mask) | ||
455 | * | ||
456 | * which is precisely what we want. | ||
457 | */ | ||
458 | #define BIO_VMERGE_BOUNDARY (ia64_max_iommu_merge_mask + 1) | ||
459 | #endif | ||
460 | |||
461 | #endif /* _ASM_IA64_IO_H */ | 437 | #endif /* _ASM_IA64_IO_H */ |