Re: [Qemu-devel] Debian 7.8.0 SPARC64 on qemu - anything i can do to speedup the emulation?

[Karel Gardas]

On Wed, Jul 29, 2015 at 12:20 PM, Dennis Luehring <address@hidden> wrote:
> Am 29.07.2015 um 11:17 schrieb Karel Gardas:
>>
>> If
>> anybody is interested I can dig those old emails.
>
>
> would be nice

Here is speed comparison:
https://lists.debian.org/debian-sparc/2015/02/msg00001.html but whole
thread started in january here:
https://lists.debian.org/debian-sparc/2015/01/msg00000.html

Mark then asked for profiles, I see I send them privately due to
attachements, the email is:

off-list as I'm attaching files which may be too bit for list. Also
I'm not sure if this is still relevant to debian-sparc@

Anyway, difference in IO is negligible. When I compile on SPARC on
tmpfs it was still 6m40s. On SPARC it's using -drive while on AArch64
it uses all the virtio optimization probably.

Anyway, with gprof you've hit the point. Attached two files (text
output from gprof). One shows profiler as a reference, just
boot/login/su root/poweroff/kill qemu and another is the same but ~5
hours of compilation of nbench2 in shell loop.

reference shows:
   %  cumulative    self              self    total
 time   seconds   seconds    calls  ms/call  ms/call name
 42.9     145.84   145.84                            cpu_sparc_exec [1]
  7.8     172.44    26.60                            tcg_optimize [2]
  4.4     187.38    14.94                            tcg_reg_alloc_op [3]
  4.4     202.20    14.82 get_physical_address_data [4]
  3.8     215.26    13.06 tcg_liveness_analysis [5]


while compile loop shows:
   %  cumulative    self              self    total
 time   seconds   seconds    calls  ms/call  ms/call name
 21.2    1008.09  1008.09                            tlb_flush_page [1]
 15.2    1731.09   723.00                            cpu_sparc_exec [2]
 13.6    2374.79   643.70                            tb_flush_jmp_cache [3]
  9.5    2823.86   449.07                            tcg_optimize [4]
  4.2    3024.26   200.40 tcg_liveness_analysis [5]


that's indeed a difference. -- I assume cpu_sparc_exec is what does
actual work here...