Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 09 May 2003 18:46:47 -0400 | From | Timothy Miller <> | Subject | Re: hammer: MAP_32BIT |
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H. Peter Anvin wrote: > Timothy Miller wrote: > >>If your program is capable of handling an address with more than 32 >>bits, what point is there giving a hint? Either your program can handle >>64-bit pointers or it cannot. Any program flexible enough to handle >>either size dynamically would expend enough overhead checking that it >>would be worse than if it just made a hard choice. >> > > > The purpose is that there is a slight task-switching speed advantage if > the address is in the bottom 4 GB. Since this affects every process, > and most processes use very little TLS, this is worthwhile. > > This is fundamentally due to a K8 design flaw.
Is there an explicit check somewhere for this? Are the page tables laid out differently?
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