Messages in this thread | | | Subject | Re: [patch] tls-2.5.31-C3 | From | Luca Barbieri <> | Date | 12 Aug 2002 16:17:30 +0200 |
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On Mon, 2002-08-12 at 17:57, Ingo Molnar wrote: > > 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. ] > > Yes but common multithreaded applications will have at least 1 for > > pthreads. > > i would not say 'common' and 'multithreaded' in the same sentence. It > might be so in the future, but it isnt today. Most modern servers (e.g. Apache2, MySQL) are multithreaded and so are large desktop applications (e.g. Evolution, Galeon, Nautilus).
> > > how did you calculate this? > > ((26 - 5) / 2000) * 100 ~= 1 > > Benchmarks done in kernel mode (2.4.18) with interrupts disabled on a > > Pentium3 running the rdtsc timed benchmark in a loop 1 million times > > with 8 unbenchmarked iterations to warm up caches and with the time to > > execute an empty benchmark subtracted. > > old libpthreads or new one? What are you asking about? (benchmarks are in kernel mode and context switch is from forked processes)
> > > glibc multithreaded applications can avoid the > > > lldt via using the TLS, and thus it's a net win. > > Surely, this patch is better than the old LDT method but much worse than > > the 2-TLS one. > > people asked for a 3rd TLS already. It would be interesting to know what they would use it for.
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