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

[Aurelien Jarno]

On 2015-08-18 06:25, Dennis Luehring wrote:
> Am 06.08.2015 um 11:00 schrieb Karel Gardas:
> >Denis, if NetBSD is fast in qemu and if it provides sparc64 user-land,
> >perhaps also its GCC is sparc64 binary and if so, then it would be
> >good if you do your original benchmark of compiling pugixml.cpp and
> >write the numbers here for comparison? I would certainly appreciate it
> >since I'll not get to this testing in foreseeable future again.
> 
> i've re-redone the benchmarks with Debian and NetBSD SPARC64
> 
> benchmarks:
> 
> compilation pugixml 1.6 pugixml.cpp:
> g++ src/pugixml.cpp -g -Wall -Wextra -Werror -pedantic -std=c++0x -c
> -MMD -MP
> 
> host: ~3 sec
> guest-debian: ~3:52.6 (32bit gcc, virtio)
> guest-debian: ~3:01.7 (32bit gcc, virtio, using the qcow2 image from an
> ramfs ramdisk)
> guest-netbsd: ~3:27.6 (64bit gcc, non-virtio)
> guest-netbsd: ~2:51.6 (64bit gcc, non-virtio, using the qcow2 image from an
> ramfs ramdisk)
> 
> runtime Aurelien Jarnos prime.c
> gcc prime.c -o prime.out -lm
> 
> host: ~2 sec
> guest-debian(-m32): ~3:37.5
> guest-debian(-m64): ~11 sec
> guest-netbsd(only -m64): ~11 sec
> 
> Aurelien Jarnos explained the "11 sec" boost running prime.c using -m64,
> but still the NetBSD 64bit gcc needs 3:27.6 to compile pugixml.cpp - its
> just one file, 1GB of RAM, no swapping
> 
> using a ramdisk gives even under debian(with virtio) a 50sek speedup, netbsd
> (without virtio) just gains 30sek

How big is the source file and the output file? I find strange that I/O
impacts so much for a compilation which should be CPU bounded. Maybe try
to add the -pipe argument to g++.

Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
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