Re: [PATCH v2 08/11] test-tool synthesize: precompute pack for 4 GiB + 1

From: Derrick Stolee <stolee@gmail.com>
Date: May 4, 2026, 18:27 UTC
Message-ID: <a382fcdf-a9c9-4caa-8be4-163c7bcbd64b@gmail.com>
In-Reply-To: <29b9a74e915e6200ac2b4d98e446c1e73964cbd2.1777914508.git.gitgitgadget@gmail.com>

On 5/4/2026 1:08 PM, Johannes Schindelin via GitGitGadget wrote:

> From: Johannes Schindelin <johannes.schindelin@gmx.de>

Show 9 quoted lines

> Benchmarks generating a 4 GiB + 1 pack (3 runs each, SHA1DC on
> x86_64):
> 
>   generic path:   88s / 81s / 140s
>   fast path:      14s / 13s / 15s
> 
> On CI, where t5608 currently takes 200-850 seconds depending on the
> job, the fast path cuts the pack-generation phase from minutes to
> seconds, leaving only the clone operations themselves.

Are these numbers accurate for the patch position in the series?

The previous change replaced SHA1DC with the unsafe version, which gained similar performance improvements. I'd be interested to see the numbers for both enabled at the same time.

Thanks, -Stolee