Messages in this thread | | | From | Denis Vlasenko <> | Subject | Re: [PATCH] 2/2 2.5.45 cleanup & add original copy_ro/from_user | Date | Sat, 2 Nov 2002 15:08:16 -0200 |
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On 2 November 2002 10:09, Andi Kleen wrote: > > That depends on size. If you do huge memcpy (say 1 mb) it still > > wins by wide margin. Not that we do such huge operations often, > > but code can check size and pick different routines for small > > and big blocks > > The kernel nevers does such huge memcpys. It rarely does handle any > buffer bigger than a page (4K)
Okay I take that.
How did you determined that movntXX stores are net loss? I thought about that and didn't came to a working solution.
It's easy to time memcpy() but harder to measure susequent cache misses when copied data gets accessed. We can read it back after memcpy and measure memcpy()+read, but is entire copy gets used immediately after memcpy() in real world usage? We're in benchmarking hell :( -- vda - 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/
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