On 6/8/22 08:29, Jakub Wartak wrote:
The attached patch is a trivial version that waits until we're at
least
32 pages behind the target, and then prefetches all of them. Maybe give it
a
>> try?
(This pretty much disables prefetching for e_i_c below 32, but for an
> >> The attached patch is a trivial version that waits until we're at
> >> least
> >> 32 pages behind the target, and then prefetches all of them. Maybe give it
> >> a
> try?
> >> (This pretty much disables prefetching for e_i_c below 32, but for an
> >> experimental patch that's enough.)
> >
>
On 6/7/22 15:29, Jakub Wartak wrote:
> Hi Tomas,
>
>>> I have a machine here with 1 x PCIe 3.0 NVMe SSD and also 1 x PCIe 4.0
>>> NVMe SSD. I ran a few tests to see how different values of
>>> effective_io_concurrency would affect performance. I tried to come up
>>> with a query that did little
Hi Tomas,
> > I have a machine here with 1 x PCIe 3.0 NVMe SSD and also 1 x PCIe 4.0
> > NVMe SSD. I ran a few tests to see how different values of
> > effective_io_concurrency would affect performance. I tried to come up
> > with a query that did little enough CPU processing to ensure that I/O
>
Hi Nathan,
> > NVMe devices have a maximum queue length of 64k:
[..]
> > but our effective_io_concurrency maximum is 1,000:
[..]
> > Should we increase its maximum to 64k? Backpatched? (SATA has a
> > maximum queue length of 256.)
>
> If there are demonstrable improvements with higher values,
On 4/21/22 10:14, David Rowley wrote:
> On Wed, 20 Apr 2022 at 14:56, Bruce Momjian wrote:
>> NVMe devices have a maximum queue length of 64k:
>
>> Should we increase its maximum to 64k? Backpatched? (SATA has a
>> maximum queue length of 256.)
>
> I have a machine here with 1 x PCIe 3.0 NVMe
On Wed, 20 Apr 2022 at 14:56, Bruce Momjian wrote:
> NVMe devices have a maximum queue length of 64k:
> Should we increase its maximum to 64k? Backpatched? (SATA has a
> maximum queue length of 256.)
I have a machine here with 1 x PCIe 3.0 NVMe SSD and also 1 x PCIe 4.0
NVMe SSD. I ran a few
On Tue, Apr 19, 2022 at 10:56:05PM -0400, Bruce Momjian wrote:
> NVMe devices have a maximum queue length of 64k:
>
> https://blog.westerndigital.com/nvme-queues-explained/
>
> but our effective_io_concurrency maximum is 1,000:
>
> test=> set effective_io_concurrency = 1001;
>
