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Re: RFC: What inputs to use for sqrt perf testing
- From: Siddhesh Poyarekar <siddhesh dot poyarekar at gmail dot com>
- To: Steve Ellcey <sellcey at mips dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Fri, 4 Oct 2013 08:09:30 +0530
- Subject: Re: RFC: What inputs to use for sqrt perf testing
- Authentication-results: sourceware.org; auth=none
- References: <cf183992-8b0e-4439-b651-f3da33cda74d at BAMAIL02 dot ba dot imgtec dot org>
On 4 October 2013 02:55, Steve Ellcey <firstname.lastname@example.org> wrote:
> While making a sqrt performance improvement for MIPS I noticed that there
> was no sqrt performance test in the 'make bench' tests and Joseph suggested
> that we should have one. It looks like adding it is trivial (see patch),
> but the real question is what input to use. I just threw in 1.9 and 10000.0
> to test this patch, but I don't think those are necessarily good choices.
> Are there any math experts out there could suggest a better selection of
> inputs for sqrt to use in the performance tests?
> Here is my strawman patch, I don't expect this to get checked in as it
> is, I am just including it for reference purposes.
The method I'm using for this is to add probes at various branch
points within the function and use a systemtap script to print out the
input whenever the probe point is hit. This is a bit slow (in terms
of effort), but would ensure good coverage. Also, as a starting
point, I wouldn't mind having your strawman patch in and then more
inputs added to it when you have them ready.