Re: [RFC PATCH 0/3] Neural Storage Driver - learning page cache prefetcher

[Jan Kara]

On Mon 10-08-26 04:13:12, Matthew Wilcox wrote:
> On Sat, Aug 08, 2026 at 05:10:42PM -0400, Ayhan Aydin wrote:
> > For reference, the series adds an optional observation hook
> > (CONFIG_NSD, default off, see PATCH 1/3) that does not bypass
> > the existing ra_state / file_ra_struct machinery. All actual
> > page insertion is still delegated to page_cache_sync_readahead().
> > Benchmarks (interleaved ON/OFF methodology, i.e. same-machine A/B
> > with repeated runs, SQLite full-table scans and buffered
> > sequential I/O) showed an 18-19% wall-time reduction and
> > +22.6% throughput improvement respectively.

I can see how SQLite table scans could be improved but I'm really surprised
by the 64k sequential buffered read. That's basically what the current
readahead logic is built for. So how is the sync readahead you trigger
better than what generic async readahead does?

								Honza
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR