From: Bagas Sanjaya Date: Wed, 26 May 2021 11:04:25 GMT Subject: Re: time needed to rebase shortend by using --onto? Message-ID: In-Reply-To: <20210526100932.2hw4rbazgvd6mzff@pengutronix.de> Hi Uwe, On 26/05/21 17.09, Uwe Kleine-König wrote: > Hello, > > I have a kernel topic branch containing 4 patches on top of Linux v5.4. > (I didn't speak to the affected customer, so I cannot easily share the > patch stack. If need be I can probably anonymize it or ask if I can > publish the patches.) > > It rebases clean on v5.10: > > $ time git rebase v5.10 > Performing inexact rename detection: 100% (36806539/36806539), done. > Performing inexact rename detection: 100% (36806539/36806539), done. > Performing inexact rename detection: 100% (36806539/36806539), done. > Performing inexact rename detection: 100% (36806539/36806539), done. > Successfully rebased and updated detached HEAD. > > real 3m47.841s > user 1m25.706s > sys 0m11.181s > > If I start with the same rev checked out and explicitly specify the > merge base, the rebase process is considerably faster: > > $ time git rebase --onto v5.10 v5.4 > Performing inexact rename detection: 100% (36806539/36806539), done. > Performing inexact rename detection: 100% (36806539/36806539), done. > Performing inexact rename detection: 100% (36806539/36806539), done. > Performing inexact rename detection: 100% (36806539/36806539), done. > Successfully rebased and updated detached HEAD. > > real 1m20.588s > user 1m12.645s > sys 0m6.733s > > Is there some relevant complexity in the first invocation I'm not seeing > that explains it takes more than the double time? I would have expected > that > > git rebase v5.10 > > does the same as: > > git rebase --onto v5.10 $(git merge-base HEAD v5.10) > > . (FTR: > > $ time git merge-base HEAD v5.10 > 219d54332a09e8d8741c1e1982f5eae56099de85 > > real 0m0.158s > user 0m0.105s > sys 0m0.052s > > , 219d5433 is v5.4 as expected. > > $ git version > git version 2.29.2 > > That's from the Debian package 1:2.29.2-1~bpo10+1 on a Debian 10 box.) > > Best regards > Uwe > Can you reproduce your findings with latest version (v2.32.0-rc1) please? -- An old man doll... just what I always wanted! - Clara