> On 2010-08-09 12:13:59, Nathan Binkert wrote:
> >
How is this not a possible issue for every isa? We're talking about touching
256kB of data. That shouldn't take very long. We've beaten this to death, it's
time to just call it done and move on. If we're that concerned just do:
for (int x = 0; x < sizeof(buf); x += 512)
buf[x] = 0;
It improves the speed by three orders of magnitude, doesn't require and ifdef
and will work on everything that doesn't have a unbelievably small page size.
- Ali
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This is an automatically generated e-mail. To reply, visit:
http://reviews.m5sim.org/r/121/#review154
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On 2010-08-09 10:35:49, Joel Hestness wrote:
>
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://reviews.m5sim.org/r/121/
> -----------------------------------------------------------
>
> (Updated 2010-08-09 10:35:49)
>
>
> Review request for Default.
>
>
> Summary
> -------
>
> util/m5/m5.c: in readfile(), added memset to touch all pages - ensure they
> are in the page table
>
> This problem is caused by Linux demand paging. If the pages are not yet
> mapped in the page table, the M5 utility does not know the physical memory
> address in the simulated system to which it is sending the file read from the
> host machine.
>
>
> Diffs
> -----
>
> util/m5/m5.c a75564db03c3
>
> Diff: http://reviews.m5sim.org/r/121/diff
>
>
> Testing
> -------
>
> This fixes the functionality for x86, where the problem was first
> encountered. I have also tested the utility for Alpha. The simulated system
> executes approximately 10% more instructions during the readfile operation
> due to the memset, but the simulation time required for this is still
> marginal. Using memset provides an ISA independent solution compared to
> buffer accesses that use a page-sized stride.
>
>
> Thanks,
>
> Joel
>
>
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