Re: Shark on MacBook Air
Re: Shark on MacBook Air
- Subject: Re: Shark on MacBook Air
- From: David Dunham <email@hidden>
- Date: Fri, 22 Feb 2008 09:46:12 -0800
On 20 Feb 2008, at 11:21, Rick Altherr wrote:
I started doing some performance analysis of a game that uses
OpenGL, and happened to be using a MacBook Air. I'm seeing results
very different than I'd expect:
0.0% 81.8% mach_kernel dtrace_get_cpu_int_stack_top
Most of this time is in
0.1% 79.8% com.apple.driver.AppleIntelGMAX3100
IOIntel965GLContext::clientMemoryForType(unsigned long, unsigned
long*, IOMemoryDescriptor**)
Without more of the tree, I can't say much as to what the root
cause it. However, it's likely that your kernel is stripped so
Shark is guessing as to which symbol contains the address in the
call stack. dtrace_get_cpu_int_stack_top was likely the closest
symbol to the address.
Thanks, that must be the issue.
I Sharked (that is a verb, right?) the same game on a machine with an
actual graphics card, and also got time in
dtrace_get_cpu_int_stack_top, that turned out to be in the graphics
driver. However, it was only about 4%, so I never noticed it before.
This was the first time I'd used Shark on a machine with integrated
video, and I had no idea it took so much CPU time.
David Dunham
Voice/Fax: 206 783 7404 http://www.pensee.com/dunham/
Imagination is more important than knowledge. -- Albert Einstein
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