|To:||Johannes Stezenbach <firstname.lastname@example.org>|
|Subject:||Re: LL/SC benchmarking [was: Mipsel libc with LL/SC online anywhere?]|
|From:||Jun Sun <email@example.com>|
|Date:||Thu, 25 Jul 2002 11:56:23 -0700|
|Cc:||"Kevin D. Kissell" <firstname.lastname@example.org>, email@example.com|
|References:||<00ce01c229a4$a7d4ed40$10eca8c0@grendel> <20020719123828.GA5521@convergence.de> <20020725162539.GA8804@convergence.de> <3D40302F.firstname.lastname@example.org> <20020725184519.GB9302@convergence.de>|
|User-agent:||Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.9) Gecko/20020408|
Johannes Stezenbach wrote:
On Thu, Jul 25, 2002 at 10:06:55AM -0700, Jun Sun wrote:Johannes Stezenbach wrote:sysmips: real 1m19.358s user 0m28.150s sys 0m47.250s LL/SC emulation: real 0m41.246s user 0m25.390s sys 0m12.240s branch-likely hack (hm, still without kernel patch...): real 0m25.126s user 0m17.240s sys 0m2.310sJohannes,This is great stuff! Can you explain what are "real", "user", and "sys"? Also, what is your initial conclusion?This are results from simple 'time ./testapp' testing, so its real time and user/system time reported by wait(4). Also, I have an interactive gtk+directfb applicaton running. The difference in response time is quite noticable. On reason for the big differences is that the Glib-2.0/GObject library does a lot of locking in its internal type system for every object created. Other software might not suffer as badly from a slow mutex implementation. My conclusion is that it is good for glibc to always use ll/sc, emulated or not, and for my specific needs I will use the branch-likely hack. So next I will study kernel source to decide what MAGIC_COOKIE is best for the branch-likely hack, and where to add 'move k1,$0' before eret. OTOH I doubt it's worth it to add the branch-likely hack to stock glibc. How many people are using Linux/MIPS on embedded CPU's without LL/SC?
There are probably more than you think. The popuplar (and notorious) NEC VR41xx family fall into this category. I think at least one or two other families of CPUs are like this too.
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