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Re: static user probe performance
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: Stan Cox <scox at redhat dot com>
- Cc: systemtap at sourceware dot org
- Date: Mon, 05 Apr 2010 11:21:23 -0400
- Subject: Re: static user probe performance
- References: <4BABACFE.60406@redhat.com> <4BB65994.5070906@redhat.com>
Stan Cox <scox@redhat.com> writes:
> [...]
> not run with stap
> [...]
> elapsed time
> volatile no semaphore 38.18
> no volatile no semaphore 48.02
> volatile semaphore 51.66
> no volatile semaphore 60.23
I don't understand these numbers. The "no volatile" version is
consistently slower than "volatile". How can that be?
> run with stap
> [...]
> elapsed time
> volatile semaphore 1858.71
> no volatile no semaphore 1865.68
> volatile no semaphore 1873.07
> no volatile semaphore 1878.09
So for this particular microbenchmark, systemtap probing imposes a 30x
slowdown, yikes. How many probe hits does this represent?
- FChE