From: Jon Steinhart <jon@fourwinds.com>
To: tuhs@tuhs.org
Subject: Re: [TUHS] block operations in editors, was My EuroBSDcon talk
Date: Tue, 17 Sep 2019 21:52:24 -0700 [thread overview]
Message-ID: <201909180452.x8I4qOiO002491@darkstar.fourwinds.com> (raw)
In-Reply-To: <2af4396e3f1133dfb93c2a92722e6f0e850ade55@webmail.yaccman.com>
Steve Johnson writes:
> This is one of my pet peeves. "Random Access" memory is far from random when
> you look at the time it takes to do the accesses. With modern memories,
> accessing a column can be 20 to 40x slower than accessing a row. This is
> particularly irritating when doing AI training, where training reuses 4-d
> tensors transposed, a very painful operation.
>
> In FORTRAN days, I once used a vector package in which you described a vector
> by giving the first element, the second element, and a count. So you could
> describe rows, columns, a matrix diagonal, and even rows and columns from back
> to front. Fortran passed arguments by address, which made the whole thing easy
> and fast.
>
> Steve
Remember the words of that great performance pioneer Jimmy Durante: ras-a-ma-cas.
next prev parent reply other threads:[~2019-09-18 4:52 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-17 17:31 Doug McIlroy
2019-09-18 4:47 ` Steve Johnson
2019-09-18 4:52 ` Jon Steinhart [this message]
-- strict thread matches above, loose matches on Subject: below --
2019-09-17 15:36 Noel Chiappa
2019-09-17 11:34 Thomas Paulsen
2019-09-17 0:20 Doug McIlroy
2019-09-17 0:42 ` G. Branden Robinson
2019-09-17 2:02 ` George Michaelson
2019-09-17 11:01 ` Thomas Paulsen
2019-09-17 1:25 ` Bakul Shah
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