site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com Ernesto. All, ml_set_interrupts_enabled thread_block_reason thread_block uiomove selprocess select Regards, _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... A blocked thread by the OS, by means of select(), read(), recv(), etc does not add up to the CPU cycles count (it's effectively sleeping, waiting for an event to occur). So you can probably safely ignore that result from Shark and move on to the other routines that are consuming the other 40% of the CPU time, and see what those routines are. Then try to figure out why are them consuming that many cycles. If the routines are OS routines, then trace back until you hit one of your program's routines, and see what calls it, and what could be wrong in that call. On Apr 11, 2007, at 3:41 PM, jmzorko@mac.com wrote: While I appreciate the info on how to use select(), that's not the nature of my question. I'll try to explain it better :-) I've a bunch of C++ code that runs on Windows and OSX. 99% of the code is portable, and the 1% that isn't mostly has to do with file operations (seeking the POSIX way is slow on Windows, so we had to use the Win32 APIs for that stuff). Anyway, with such a large majority of our code the same across both operating systems, I was expecting to see more-or-less-comparable CPU usage. However, when I run the code, I see the OSX version taking up 4-5x (or more, sometimes 10x) as much CPU as it does under Windows -- this is on my dual 2ghz G5 as well as my 2ghz Core Duo MacBook. So, I said to myself, "self, you should check out that nifty Shark app that ships with OSX, and see if you can find out what is taking all the CPU" So, I did. I launched Shark, pointed it at my process, selected Time Profile, and pressed Start. A minute or so later, it came back and showed me lots of cool stuff, but the most interesting thing was that, according to Shark, something like 60% of the time my program was running, it was in ml_set_interrupts_enabled. I said, "self, I don't know what that is, but let's see if it calls something that I do know about." So I followed the arrows, and this is what Shark told me: ... so the nature of my question is this: if 60% of the time my program is running is spent in the above, how can I optimize it? Or am I interpreting the output of Shark correctly (for instance, does ml_set_interrupts_enabled call thread_block_reason which calls thread_block, or vice versa)? John This email sent to site_archiver@lists.apple.com