Re: [PATCH 1/1] merge-ort: begin performance work; instrument with trace2_region_* calls

From: Taylor Blau <ttaylorr@github.com>
Date: Jan 8, 2021, 20:59 UTC
Message-ID: <X/jHpZlSxwAxoUyq@nand.local>
In-Reply-To: <20210108205111.2197944-2-newren@gmail.com>

On Fri, Jan 08, 2021 at 12:51:11PM -0800, Elijah Newren wrote:

> Overall timings, using hyperfine (1 warmup run, 3 runs for mega-renames,
> 10 runs for the other two cases):

Ah, I love hyperfine. In case you don't already have this in your arsenal, the following `--prepare` step is useful for measuring cold-cache performance:

    --prepare='sync; echo 3 | sudo tee /proc/sys/vm/drop_caches'

Show 11 quoted lines

> === Goals ===
>
> This patch is obviously just the beginning.  Here are some of my goals
> that this measurement will help us achieve:
>
> * Drive the cost of rename detection down considerably for merges
> * After the above has been achieved, see if there are other slowness
>   factors (which would have previously been overshadowed by rename
>   detection costs) which we can then focus on and also optimize.
> * Ensure our rebase testcase that requires little rename detection
>   is noticeably faster with merge-ort than with apply-based rebase.

These are great, and I am looking forward to your work.

> Signed-off-by: Elijah Newren <newren@gmail.com>

Thanks, this patch looks good to me.

Thanks, Taylor