Messages in this thread | | | Date | Mon, 12 Aug 2002 17:12:41 +0200 (CEST) | From | Ingo Molnar <> | Subject | Re: [patch] tls-2.5.31-C3 |
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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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