From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Ritesh Harjani <riteshh@linux.ibm.com>
Cc: linux-ext4@vger.kernel.org, jack@suse.cz,
dan.j.williams@intel.com, anju@linux.vnet.ibm.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv3 1/1] ext4: Optimize file overwrites
Date: Sat, 3 Oct 2020 00:49:05 -0400 [thread overview]
Message-ID: <20201003044905.GF23474@mit.edu> (raw)
In-Reply-To: <88e795d8a4d5cd22165c7ebe857ba91d68d8813e.1600401668.git.riteshh@linux.ibm.com>
On Fri, Sep 18, 2020 at 10:36:35AM +0530, Ritesh Harjani wrote:
> In case if the file already has underlying blocks/extents allocated
> then we don't need to start a journal txn and can directly return
> the underlying mapping. Currently ext4_iomap_begin() is used by
> both DAX & DIO path. We can check if the write request is an
> overwrite & then directly return the mapping information.
>
> This could give a significant perf boost for multi-threaded writes
> specially random overwrites.
> On PPC64 VM with simulated pmem(DAX) device, ~10x perf improvement
> could be seen in random writes (overwrite). Also bcoz this optimizes
> away the spinlock contention during jbd2 slab cache allocation
> (jbd2_journal_handle). On x86 VM, ~2x perf improvement was observed.
>
> Reported-by: Dan Williams <dan.j.williams@intel.com>
> Suggested-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Thanks, applied.
- Ted
prev parent reply other threads:[~2020-10-03 4:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 5:06 [PATCHv3 0/1] Optimize ext4 file overwrites - perf improvement Ritesh Harjani
2020-09-18 5:06 ` [PATCHv3 1/1] ext4: Optimize file overwrites Ritesh Harjani
2020-09-18 7:52 ` Sedat Dilek
2020-09-18 9:52 ` Jan Kara
2020-09-25 7:12 ` [ext4] 4e8fc10115: fio.write_iops 330.6% improvement kernel test robot
2020-10-03 4:49 ` Theodore Y. Ts'o [this message]
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