On 12 Aug 2002, Luca Barbieri wrote:
> Numbers:
> unconditional copy of 2 tls descs: 5 cycles
> this patch with 1 tls desc: 26 cycles
> this patch with 8 tls descs: 52 cycles
[ 0 tls descs: 2 cycles. ]
but yes, this is rougly what i'd say this approach costs.
> lldt: 51 cycles
> lgdt: 50 cycles
> context switch: 2000 cycles (measured with pipe read/write and vmstat so
> it's not very accurate)
> So this patch causes a 1% context switch performance drop for
> multithreaded applications.
how did you calculate this? glibc multithreaded applications can avoid the
lldt via using the TLS, and thus it's a net win.
Ingo
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This archive was generated by hypermail 2b29 : Thu Aug 15 2002 - 22:00:27 EST