lkml.org 
[lkml]   [2006]   [Jun]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [RFC, patch] i386: vgetcpu(), take 2
    From
    Date
    On Wed, 2006-06-21 at 11:26 +0200, Andi Kleen wrote:
    > Chuck Ebbert <76306.1226@compuserve.com> writes:
    >
    > > Use a GDT entry's limit field to store per-cpu data for fast access
    > > from userspace, and provide a vsyscall to access the current CPU
    > > number stored there.
    >

    Very clever.

    > Just the CPU alone is useless - you want at least the node too in many
    > cases. Best you use the prototype I proposed earlier for x86-64.
    >

    Can we use similar mechanism to access pda in vsyscall in x86_64 (by
    storing the address of pda there). That way the useful variables like
    cpunumber, nodenumber can be accessed easily without doing cpuid (and
    without tcache). The system call can take a flag like GET_CPUNUMBER or
    GET_NODENUMBER or GET_NMICOUNT or if anything new gets added in this
    structure.

    -rohit

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2006-06-21 23:59    [W:3.644 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site