[RFC PATCH -V2 00/21] THP support for PPC64

[Simon Jeons]

Hi Aneesh,
On 02/22/2013 12:47 AM, Aneesh Kumar K.V wrote:
> Hi,
>
> This patchset adds transparent huge page support for PPC64.
>
> I am marking the series to linux-mm because the PPC64 implementation
> required few interface changes to core THP code. I still have considerable
> number of FIXME!! in the patchset mostly related to PPC64 mm susbsytem.
> Those would require closer review and once we are clear on those changes,
> I will drop those FIXME!! with necessary comments.
>
> Some numbers:
>
> The latency measurements code from Anton  found at
> http://ozlabs.org/~anton/junkcode/latency2001.c

Can this benchmark use for x86?

>
> THP disabled 64K page size
> ------------------------
> [root at llmp24l02 ~]# ./latency2001 8G
>   8589934592    731.73 cycles    205.77 ns
> [root at llmp24l02 ~]# ./latency2001 8G
>   8589934592    743.39 cycles    209.05 ns
> [root at llmp24l02 ~]#
>
> THP disabled large page via hugetlbfs
> -------------------------------------
> [root at llmp24l02 ~]# ./latency2001  -l 8G
>   8589934592    416.09 cycles    117.01 ns
> [root at llmp24l02 ~]# ./latency2001  -l 8G
>   8589934592    415.74 cycles    116.91 ns
>
> THP enabled 64K page size.
> ----------------
> [root at llmp24l02 ~]# ./latency2001 8G
>   8589934592    405.07 cycles    113.91 ns
> [root at llmp24l02 ~]# ./latency2001 8G
>   8589934592    411.82 cycles    115.81 ns
> [root at llmp24l02 ~]#
>
>
> We are close to hugetlbfs in latency and we can achieve this with zero
> config/page reservation. Most of the allocations above are fault allocated.
> I haven't really measured the collapse alloc impact.
>
> Another test that does 50000000 random access over 1GB area goes from
> 2.65 seconds to 1.07 seconds with this patchset.
>
> Changes from RFC V1:
> * HugeTLB fs now works
> * Compile issues fixed
> * rebased to v3.8
> * Patch series reorded so that ppc64 cleanups and MM THP changes are moved
>    early in the series. This should help in picking those patches early.
>
> Thanks,
> -aneesh
>
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