From: Matthew Wilcox <willy@infradead.org>
To: Kent Overstreet <kent.overstreet@gmail.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
viro@zeniv.linux.org.uk, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 2/2] fs: generic_file_buffered_read() now uses find_get_pages_contig
Date: Tue, 9 Jun 2020 18:38:08 -0700 [thread overview]
Message-ID: <20200610013808.GF19604@bombadil.infradead.org> (raw)
In-Reply-To: <20200610001036.3904844-3-kent.overstreet@gmail.com>
On Tue, Jun 09, 2020 at 08:10:36PM -0400, Kent Overstreet wrote:
> Convert generic_file_buffered_read() to get pages to read from in
> batches, and then copy data to userspace from many pages at once - in
> particular, we now don't touch any cachelines that might be contended
> while we're in the loop to copy data to userspace.
>
> This is is a performance improvement on workloads that do buffered reads
> with large blocksizes, and a very large performance improvement if that
> file is also being accessed concurrently by different threads.
Hey, you're stealing my performance improvements!
Granted, I haven't got to doing performance optimisations (certainly
not in this function), but this is one of the places where THP in the
page cache will have a useful performance improvement.
I'm not opposed to putting this in, but I may back it out as part of
the THP work because the THPs will get the same performance improvements
that you're seeing here with less code.
next prev parent reply other threads:[~2020-06-10 1:38 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 0:10 [PATCH 0/2] generic_file_buffered_read() refactoring & optimization Kent Overstreet
2020-06-10 0:10 ` [PATCH 1/2] fs: Break generic_file_buffered_read up into multiple functions Kent Overstreet
2020-06-10 0:10 ` [PATCH 2/2] fs: generic_file_buffered_read() now uses find_get_pages_contig Kent Overstreet
2020-06-10 0:47 ` Matthew Wilcox
2020-06-10 1:08 ` Kent Overstreet
2020-06-10 1:38 ` Matthew Wilcox [this message]
2020-06-10 1:46 ` Kent Overstreet
2020-06-20 14:36 ` [fs] 420772c473: vm-scalability.throughput 41.7% improvement kernel test robot
2020-06-10 1:36 ` [PATCH v2 1/2] fs: Break generic_file_buffered_read up into multiple functions Kent Overstreet
2020-06-10 1:36 ` [PATCH v2 2/2] fs: generic_file_buffered_read() now uses find_get_pages_contig Kent Overstreet
2020-06-18 1:05 ` Andrew Morton
2020-06-19 3:20 ` [PATCH v3 0/2] generic_file_buffered_read() refactoring & optimization Kent Overstreet
2020-06-19 12:59 ` Christoph Hellwig
2020-06-19 18:44 ` Kent Overstreet
2020-06-19 3:20 ` [PATCH v3 1/2] fs: Break generic_file_buffered_read up into multiple functions Kent Overstreet
2020-06-19 3:20 ` [PATCH v3 2/2] fs: generic_file_buffered_read() now uses find_get_pages_contig Kent Overstreet
2020-06-30 0:12 ` Fixup patch for [PATCH 0/2] generic_file_buffered_read() refactoring & optimization Kent Overstreet
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