2018-03-31 13:42 GMT+02:00 Jaromír Doleček :
> 2018-03-25 17:27 GMT+02:00 Joerg Sonnenberger :
>> Yeah, that's what ephemeral mappings where supposed to be for. The other
>> question is whether we can't just use the direct map for this on amd64
>> and similar platforms?
>
> Right, we could/should u
On Mon, Apr 02, 2018 at 09:28:43PM +0200, Jaromír Dole?ek wrote:
> The only port actually having optimization for emap is x86. Since amd64
> is also the only one supporting direct map, we are really at liberty to pick
> either one.
I am not sure what you mean here - AFIK alpha and mips64 also have
Le 02/04/2018 à 21:28, Jaromír Doleček a écrit :
2018-03-31 13:42 GMT+02:00 Jaromír Doleček :
2018-03-25 17:27 GMT+02:00 Joerg Sonnenberger :
Yeah, that's what ephemeral mappings where supposed to be for. The other
question is whether we can't just use the direct map for this on amd64
and simil
> 4GB of KVA; and in addition pmap_kernel will consume some KVA too. i386 for
> example has only 4GB of ram and 4GB of KVA, so we'll just never add a direct
> map there.
note that it changes your direct map point, but, i386 GENERIC_PAE
works fine for at least 16GB ram. it should work upto 64GB.
I've finally got my test rig setup, so was able to check the
performance difference when using emap.
Good news there is significant speedupon NVMe device, without
observing any bad side effects so far.
I've setup a test file of 2G, smaller than RAM to fit all in cache, test was:
dd if=foo of=/dev
I've modified the uvm_bio.c code to use direct map for amd64. Change
seems to be stable, I've also run 'build.sh tools' to test out the
system, build suceeded and I didn't observe any problems with
stability. Test was on 6-core Intel CPU with HT on (i.e. "12" cores
visible to OS), NVMe disk, cca 2G
> On May 11, 2018, at 8:28 AM, Jaromír Doleček
> wrote:
>
> I've modified the uvm_bio.c code to use direct map for amd64. Change
> seems to be stable, I've also run 'build.sh tools' to test out the
> system, build suceeded and I didn't observe any problems with
> stability. Test was on 6-core
On Fri, May 11, 2018 at 05:28:18PM +0200, Jaromír Dole?ek wrote:
> I've implemented a tweak to read-ahead code to skip the full
> read-ahead if last page of the range is already in cache, this
> improved things a lot:
That looks a bit like a hack. Can't you just call uvm_pagelookup()
to determine
2018-05-12 7:07 GMT+02:00 Michael van Elst :
> On Fri, May 11, 2018 at 05:28:18PM +0200, Jaromír Dole?ek wrote:
>> I've implemented a tweak to read-ahead code to skip the full
>> read-ahead if last page of the range is already in cache, this
>> improved things a lot:
>
> That looks a bit like a hac
hi,
sorry for being so late to the party on this thread,
I should have replied long ago.
On Fri, May 11, 2018 at 05:28:18PM +0200, Jaromr Dole?ek wrote:
> I've modified the uvm_bio.c code to use direct map for amd64. Change
> seems to be stable, I've also run 'build.sh tools' to test out the
> s
2018-05-12 21:24 GMT+02:00 Chuck Silvers :
> the problem with keeping the pages locked (ie. PG_BUSY) while accessing
> the user address space is that it can lead to deadlock if the page
> we are accessing via the kernel mapping is the same page that we are
> accessing via the user mapping.
The pag
On Sun, May 13, 2018 at 02:59:50PM +0200, Jaromr Dole?ek wrote:
> 2018-05-12 21:24 GMT+02:00 Chuck Silvers :
> > the problem with keeping the pages locked (ie. PG_BUSY) while accessing
> > the user address space is that it can lead to deadlock if the page
> > we are accessing via the kernel mapping
2018-05-12 21:24 GMT+02:00 Chuck Silvers :
> the problem with keeping the pages locked (ie. PG_BUSY) while accessing
> the user address space is that it can lead to deadlock if the page
Meanwhile I've tested this scenario - wrote a test program to do
mmap(2) for file, then calling write() using th
On 6/10/2018 3:02 PM, Jaromír Doleček wrote:
2018-05-12 21:24 GMT+02:00 Chuck Silvers :
the problem with keeping the pages locked (ie. PG_BUSY) while accessing
the user address space is that it can lead to deadlock if the page
Meanwhile I've tested this scenario - wrote a test program to do
mma
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