Re: [eigen] Help needed to run a benchmark on many machines |

[ Thread Index | Date Index | More lists.tuxfamily.org/eigen Archives ]

*To*: eigen <eigen@xxxxxxxxxxxxxxxxxxx>*Subject*: Re: [eigen] Help needed to run a benchmark on many machines*From*: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>*Date*: Wed, 18 Feb 2015 16:12:02 -0500*Dkim-signature*: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=64acJxlXKZ6fmVM5cwbQKUnekRFYtS1lHFotq2Z1tVc=; b=01D5s1S/TerhsOTbM1jT8fqIAcj8Koz87u20TVtb2teaW48KUTVDYkLN3LODDUCydQ gTd2qV4Pb7OpekU3hMMDdYBvCKTr/SaC6n3HCGR/vVHVhHHK8TJlp8/UMnLfDhodZZDQ 7xV1QvHNXcwoy5zHVDxKHy7h4YTDA0cIRnVXM0eg/lLhAQ9UfPAeI08e4zAmA5qD6oOa Hxf+ImNTu+BLT43GxUiZa/rJFDyg8SiB/dAFvXiC0dM0BjMPQhV0JfnS4/34rWOmyuls gq9DXdW2P2/ewAb/JAaMgWcQQU8VjMOJ0eXFQZPtXBXRc3Ozwoursvf0EUN3/UzdFE3U izsg==

2015-02-18 16:04 GMT-05:00 Ilja Honkonen <ilja.j.honkonen@xxxxxxxxx>:

Oh - I guess you mean in case a matrix got allocated at the same address

as a previous one, and not initialized. But the benchmark initializes

all the matrix coefficients anyway, so IIUC it should be pretty

deterministic in this respect.

For example this code:

double starttime = time();

for (int i = 0; i < iters_at_a_time; i++) {

c = a * b;

}

double endtime = time();

is probably not the most representative one, or maybe it depends a lot on what a function does. I think for one time calculations the above loop won't tell much since a, b and c are already in cache for all but the first iteration so memory transfers won't show up. Maybe this is why in some cases one doesn't see much difference between different block sizes.

Ah, good point. I guess I had in mind a situation where whole matrices a,b,c would each be bigger than cache. For example, 1kx1k float matrices (4M) on a typical ARM CPU (1M cache). But indeed, my benchmark also aims to measure much smaller cases, so that's a problem. Any suggestions welcome on how to address this!

Benoit

Ilja

**Follow-Ups**:**Re: [eigen] Help needed to run a benchmark on many machines***From:*Ilja Honkonen

**References**:**[eigen] Help needed to run a benchmark on many machines***From:*Benoit Jacob

**Re: [eigen] Help needed to run a benchmark on many machines***From:*Hauke Heibel

**Re: [eigen] Help needed to run a benchmark on many machines***From:*Benoit Jacob

**Re: [eigen] Help needed to run a benchmark on many machines***From:*Hauke Heibel

**Re: [eigen] Help needed to run a benchmark on many machines***From:*Ilja Honkonen

**Re: [eigen] Help needed to run a benchmark on many machines***From:*Benoit Jacob

**Re: [eigen] Help needed to run a benchmark on many machines***From:*Benoit Jacob

**Re: [eigen] Help needed to run a benchmark on many machines***From:*Ilja Honkonen

**Messages sorted by:**[ date | thread ]- Prev by Date:
**Re: [eigen] Help needed to run a benchmark on many machines** - Next by Date:
**Re: [eigen] Help needed to run a benchmark on many machines** - Previous by thread:
**Re: [eigen] Help needed to run a benchmark on many machines** - Next by thread:
**Re: [eigen] Help needed to run a benchmark on many machines**

Mail converted by MHonArc 2.6.19+ | http://listengine.tuxfamily.org/ |