Re: [9front] vmx(1) OpenBSD: SSD vs sparse file

Re: [9front] vmx(1) OpenBSD: SSD vs sparse file

[Nick Owens]

could be due to the in-memory block cache that hjfs has? if a program
(like vmx) talks to devsd directly (/dev/sdE0/openbsd or whatever)
there's no cache.
On Wed, Nov 14, 2018 at 7:20 PM <sl@stanleylieber.com> wrote:
>
> Subjective observation:
>
> On my CORE i7 ThinkPad X250, vmx(1) seems to run OpenBSD/amd64 6.3
> appreciably faster when OpenBSD is installed in a sparse file stored
> on the 9front hjfs file system (which is itself running on an SSD)
> than when OpenBSD is installed on its own SSD and vmx(1) is accessing
> its hard drive directly via the -d flag.
>
> sl

Re: [9front] vmx(1) OpenBSD: SSD vs sparse file

[Matthew Veety]

On Wednesday, 14 November 2018 23:54:15 EST you wrote:
> could be due to the in-memory block cache that hjfs has? if a program
> (like vmx) talks to devsd directly (/dev/sdE0/openbsd or whatever)
> there's no cache.
> 
> On Wed, Nov 14, 2018 at 7:20 PM <sl@stanleylieber.com> wrote:
> > Subjective observation:
> > 
> > On my CORE i7 ThinkPad X250, vmx(1) seems to run OpenBSD/amd64 6.3
> > appreciably faster when OpenBSD is installed in a sparse file stored
> > on the 9front hjfs file system (which is itself running on an SSD)
> > than when OpenBSD is installed on its own SSD and vmx(1) is accessing
> > its hard drive directly via the -d flag.
> > 
> > sl

That's definitely it. I'd be willing to bet if you were doing positively 
pathological I/O (like running bonnie's random i/o test or so) performance 
would be the same or maybe very slightly slower on hjfs.

-- 
Veety

Re: [9front] vmx(1) OpenBSD: SSD vs sparse file

[Stanley Lieber]

iirc i never even tried with a sparse file before. it’s almost usable.

sl

Re: [9front] vmx(1) OpenBSD: SSD vs sparse file

[hiro]

don't know if bonnie is needed. try dd with different block sizes to
figure out what's fast and what's slow (probably as mveety says, high
bandwidth writes really benefit from cache, low bandwidth reads
shouldn't be faster on hjfs unless it's already in cache.

Re: [9front] vmx(1) OpenBSD: SSD vs sparse file

[Stanley Lieber]

i was able to surf ebay almost tolerably in chromium, which was not really tolerable at all using my disk install of openbsd.

today i’ll try gimp.

previously, i had assumed most of the slowness was down to graphics.

sl