From: Rich Felker <dalias@aerifal.cx>
To: musl@lists.openwall.com
Subject: Re: capset() capget() syscalls
Date: Sun, 9 Sep 2012 16:14:01 -0400 [thread overview]
Message-ID: <20120909201401.GG27715@brightrain.aerifal.cx> (raw)
In-Reply-To: <CAK4o1WyA=eadYzbyajKXoaYcDfqdfk8cQ3v=LJWkFzrqkQOmdA@mail.gmail.com>
On Sun, Sep 09, 2012 at 09:04:02PM +0100, Justin Cormack wrote:
> On Sat, Sep 8, 2012 at 11:14 PM, Rich Felker <dalias@aerifal.cx> wrote:
> > Is there any legitimate user of this horrible API? Last I checked
> > these functions were only useful for block-aligned IO on block devices
> > and the impression I got was that they were designed solely for
> > Oracle's use. (puke) I suppose they could be useful for FUSE drivers
> > too, however. We can add them if they have legitimate software that
> > needs them.
>
> It is still the only way to get decent io performance out of an SSD as
> far as I can see, being about a factor of 8 faster than anything else
> for random reads eg posix aio. Assuming of course our reads are block
> aligned.
If the normal Linux block cache system is even 25% slower than
low-level IO on the device without any operating system at all, that's
a major bug they need to fix. Adding hideous APIs to for userspace
apps to do their own low-level IO is not a solution. 8x is just
atrocious. Where does that figure come from?
In fairness, if you're comparing to POSIX aio, that's a pretty bad API
too. A thread performing standard blocking pread/pwrite should give
the ideal performance.
Rich
next prev parent reply other threads:[~2012-09-09 20:14 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-27 11:51 igmar
2012-09-05 6:19 ` Rich Felker
2012-09-05 9:28 ` Igmar Palsenberg
2012-09-05 14:24 ` Rich Felker
2012-09-05 17:01 ` Justin Cormack
2012-09-06 3:04 ` Rich Felker
2012-09-06 3:10 ` John Spencer
2012-09-06 3:20 ` Rich Felker
2012-09-06 3:28 ` Kurt H Maier
2012-09-06 3:41 ` Rich Felker
2012-09-06 4:41 ` Kurt H Maier
2012-09-06 8:22 ` Justin Cormack
2012-09-06 9:28 ` Szabolcs Nagy
2012-09-06 14:23 ` Rich Felker
2012-09-07 4:56 ` Rich Felker
2012-09-08 16:02 ` Justin Cormack
2012-09-08 22:14 ` Rich Felker
2012-09-09 20:04 ` Justin Cormack
2012-09-09 20:14 ` Rich Felker [this message]
2012-09-09 21:13 ` James Cloos
2012-09-09 21:55 ` Rich Felker
2012-09-09 22:12 ` Justin Cormack
2012-09-09 22:29 ` Rich Felker
2012-09-09 22:37 ` Justin Cormack
2012-09-10 15:07 ` James Cloos
2012-09-08 21:25 ` Justin Cormack
2012-09-08 22:15 ` Rich Felker
2012-09-08 23:56 ` Rich Felker
2012-09-09 0:21 ` Rich Felker
2012-09-09 8:21 ` Justin Cormack
2012-09-09 19:40 ` Justin Cormack
2012-09-09 21:02 ` Rich Felker
2012-09-09 21:07 ` Justin Cormack
2012-09-09 21:23 ` Justin Cormack
2012-09-09 21:31 ` Justin Cormack
2012-09-09 21:58 ` Rich Felker
2012-09-09 22:14 ` Justin Cormack
2012-09-15 1:54 ` Rich Felker
2012-09-16 14:13 ` Justin Cormack
2012-09-17 2:27 ` Rich Felker
2012-09-06 11:47 ` Igmar Palsenberg
2012-09-06 11:36 ` Igmar Palsenberg
2012-09-06 14:11 ` Rich Felker
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