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Peter Anvin" , Alexander Lobakin , Jakub Kicinski Subject: Re: proposition for fixing Y292B bug Message-ID: References: <3be3235a-dea7-a5ca-b5ea-4047bdeb695d@dpolakovic.space> <9e3b638d-76f2-8520-2a24-7de0cd0bc149@dpolakovic.space> <20240704174917.GB973460@mit.edu> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ovKb/ULBbS7EEMhq" Content-Disposition: inline In-Reply-To: <20240704174917.GB973460@mit.edu> --ovKb/ULBbS7EEMhq Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jul 04, 2024 at 01:49:17PM -0400, Theodore Ts'o wrote: > On Wed, Jul 03, 2024 at 05:29:58PM +0200, David Polakovic wrote: > >=20 > > I am not sure if I don't understand your solution, but extending the > > memory designation from 64 to 128 bits, is another temporary > > solution, which will again overflow one day. > >=20 > > The sole reason why I was proposing the new "BigInt" type was to > > store each digit of the time_c as separate element of array, which > > could be resized (added one digit) as needed. The only limit would > > then be the physical amount of memory in the machine. >=20 > You state that you're not experienced enough to be able to send "a > merge request". Fair enough; you also apparently don't know that > github merges is not how kernel patches are submitted, reviewed, and > integrated. tl;dr: Documentation/process/submitting-patches.rst. >=20 > What you apparently don't appreciate it is that performance is > something that is critically important for the Linux kernel, and using > multiple precision integers is not really compatible with the best and > highest performance. Computer Science is an engineering discipline, > and it's all about tradeoffs. You could enginere a plane that can > travel faster than the speed of sound, but if that compromises fuel > efficiency and annoying people who are below its flight path, pursuing > speed at all costs is not going to lead to commercial success. > (Exhibit 1: The Concorde). >=20 > Similarly, trying to make sure that software will work in the year 292 > Billion AD might not be all something that most people would consider > high priority. After all, it's.... unlikely... that the x86_64 > architecture will still be what we will be using 290 billion years > from now. So if we need recompile the kernel sometime in the next 100 > billion years for some new CPU architecture, and if it's unlikely that > hard drives brought brand new are likely to be still in operation a > decade or two from now --- there is plenty of time to evolve the > on-disk format before a billion years go by, let alone 100 billion or > 200 billion years. That was what I thought when I first read this thread (good CS principle but questionable from engineering perspective). >=20 > Finally, kernel development is driven by people who are willing to do > the work. If you want to demonstrate that it's possible to use MP > integer mathematicswithout horribly comprmising performance, then you > need to do the work. (BTW, if you don't know what the term "cache > line" means, then I encourage that you understand that first.) But > dropping a pointer to a blog post and expecting that people to do your > homework for you is not really realistic. Oh, I missed that "DIY" nature. Thanks. --=20 An old man doll... just what I always wanted! - Clara --ovKb/ULBbS7EEMhq Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQSSYQ6Cy7oyFNCHrUH2uYlJVVFOowUCZof/PQAKCRD2uYlJVVFO oweCAQDSCmO1EUVhziDTENqeEGG2pF68icNKgbnPJN3lUgMaHwD7BmTIaFbTvVLC 2PKAuvz/rKMPekVqomoV9Xu2M3zAMgY= =2LFz -----END PGP SIGNATURE----- --ovKb/ULBbS7EEMhq--