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Re: Seeking consensus on BZ 16734
- From: Rich Felker <dalias at libc dot org>
- To: Andreas Schwab <schwab at suse dot de>
- Cc: Paul Pluzhnikov <ppluzhnikov at google dot com>, "H.J. Lu" <hjl dot tools at gmail dot com>, GLIBC Devel <libc-alpha at sourceware dot org>, Daniel Colascione <dancol at dancol dot org>, Andrew Pinski <pinskia at gmail dot com>
- Date: Mon, 2 Feb 2015 14:51:13 -0500
- Subject: Re: Seeking consensus on BZ 16734
- Authentication-results: sourceware.org; auth=none
- References: <CALoOobP_7jpdZUqSFmKCTFds6t8TTdnxfOfg2jCTr_TjvU+t2w at mail dot gmail dot com> <CAMe9rOrp6jCuPe4ZX-kdHdO_4_k-Dpf7ha-PxtCJmJLnL3K0-A at mail dot gmail dot com> <CALoOobMZFx7c+i0GCFRg1-1Z=2H3xDDH8+td-D=0k9muAFvPAA at mail dot gmail dot com> <20150202051410 dot GG23507 at brightrain dot aerifal dot cx> <mvma90wipim dot fsf at hawking dot suse dot de>
On Mon, Feb 02, 2015 at 11:20:01AM +0100, Andreas Schwab wrote:
> Rich Felker <email@example.com> writes:
> > The original idea seems to be some misguided idea that read/write
> > should perform better with a page-aligned buffer. I can't make any
> > sense of this believe except in the case of the O_DIRECT silliness
> > Linux supports; normally IO is going to be memcpy to/from fs cache
> > buffers and there's no reason to expect page alignment to make that
> > faster.
> Page aligned copies from the page cache should be faster.
I acknowledge that this is the claimed reason, but I call it cargo
cult nonsense. I have not seen any technical justification for this