Mail Archives: cygwin/2005/05/28/02:10:15
On Fri, May 27, 2005 at 09:54:28PM -0700, Andy Ross wrote:
>Christopher Faylor wrote:
>>Gee, I'm sorry you thought I was being "snippy". You apparently missed
>>that I was just providing you with some obvious advice.
>
>Indeed. To paraphrase: "Fix it yourself, not my problem."
Actually, I think I implied that you should "learn more about cygwin"
and that you should "instrument it yourself".
I should also have said "check out http://cygwin.com/problems.html ".
This would have provided you with some more details to provide like
the important one of providing cygcheck output.
>> It seems like if this was a really serious problem you'd be actively
>> working towards solving it rather than sending out email and hoping
>> to get lucky.
>
>You mean, like the several hours it took to get from "FlightGear
>startup is slow" (on a platform I don't use) to the freakishly obvious
>sample code I sent you that you didn't even bother to try?
Ok. I tried it. I did not notice anything like what you described. I
saw no indication that malloc was being called after the original
startup. I saw consistent (implied) ~3 millisecond waits for disk
reads. I saw no indication of malloc activity once the reads started.
>The saddest part of all of this was when I actually did go to the CVS
>to look at the malloc synchronization and discovered that *YOU* are
>the author. So much for getting this fixed any time soon. Not my
>platform, not my problem.
Yes. I'm the author of a large percentage of the code in cygwin.
malloc synchronization is a "muto" in cygwin. I wrote the muto
implementation. I wrote it to theoretically speed up the previous
implementation. I really don't think that has anything to do with this,
however.
>Someday, you might actually care about why cygwin is so much slower
>than linux (or windows, or mingw) on the same hardware. When you do,
>you know where to find your test case. Maybe there are some other
>developers around that might want to help.
It is a very well known fact that cygwin is slow. I know several
reasons why cygwin is slow. There are undoubtedly many that I'm not
aware of.
>Again, just in case you aren't clear or if someone else wants to
>inject some sanity into the conversation: Cygwin is SLOW AS MOLASSES
>(literally: fifteen times slower than mingw or glibc) when doing
>obscure tasks like reading lines, splitting them into fields, and
>allocating memory to hold the strings.
>
>This is probably also why Cygwin is so much slower than linux or mingw
>at so many other tasks. That you don't think this is a problem is
>just beyond me.
Again, I'd suggest that you spend a little more time looking at the
problem and instrumenting parts of the code that you think are giving
you problems. You should probably take c++ out of the equation, too.
There's no way of knowing if something in c++ is causing the problem
that you're seeing.
All that I'm asking you to do is prove your *guess* that this is a
malloc problem.
cgf
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