forked from luck/tmp_suning_uos_patched
1f9cc3cb6a
While testing an application using the xpmem (out of kernel) driver, we noticed a significant page fault rate reduction of x86_64 with respect to ia64. For one test running with 32 cpus, one thread per cpu, it took 01:08 for each of the threads to vm_insert_pfn 2GB worth of pages. For the same test running on 256 cpus, one thread per cpu, it took 14:48 to vm_insert_pfn 2 GB worth of pages. The slowdown was tracked to lookup_memtype which acquires the spinlock memtype_lock. This heavily contended lock was slowing down vm_insert_pfn(). With the cmpxchg on page->flags method, both the 32 cpu and 256 cpu cases take approx 00:01.3 seconds to complete. Signed-off-by: Robin Holt <holt@sgi.com> LKML-Reference: <20100423153627.751194346@gulag1.americas.sgi.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@gmail.com> Cc: Rafael Wysocki <rjw@novell.com> Reviewed-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> |
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| alpha | ||
| arm | ||
| avr32 | ||
| blackfin | ||
| cris | ||
| frv | ||
| h8300 | ||
| ia64 | ||
| m32r | ||
| m68k | ||
| m68knommu | ||
| microblaze | ||
| mips | ||
| mn10300 | ||
| parisc | ||
| powerpc | ||
| s390 | ||
| score | ||
| sh | ||
| sparc | ||
| um | ||
| x86 | ||
| xtensa | ||
| .gitignore | ||
| Kconfig | ||