# [GSoC] Git Blog 7 2 messages from 2021-07-04 to 2021-07-05. Participants: ZheNing Hu, Christian Couder. Thread: https://gitlist.dev/t/56047 ## ZheNing Hu, 2021-07-04 14:42 Subject: [GSoC] Git Blog 7 Message-ID: URL: https://gitlist.dev/e/CAOLTT8R_%3D8Md3vk5yBK4dggq1RKof_6c1tOEtfchbSmYf%2BgwtA%40mail.gmail.com ``` My seventh week blog finished: The web version is here: https://adlternative.github.io/GSOC-Git-Blog-7/ ## Week7 Performance Testing 2 This week I used performance flame graph at the suggestion of my mentor `Christian` to find out where my patch affected the performance of `cat-file --batch`. `oid_object_info_extended()` takes the largest proportion of time, accounting for `90.28%` and `41.60%` in `cat-file --batch` and `cat-file --batch-check` respectively. Part of the reason is that `oid_object_info_extended()` is called twice in `get_object()` with my patch. I tried to revise its logic (`WIP`), the performance is improved when without using `--textconv` and `--filters`. `Ævar Arnfjörð Bjarmason` gave me a good suggestion on performance regression: When we use the default format of `git cat-file --batch-check` or `git cat-file --batch`, we can directly print the meta-data of the object without going through the logic of `ref-filter`; When we use other format, use the logic in ref-filter. In addition, `Ævar Arnfjörð Bjarmason` also suggests adding a performance test for `git cat-file --batch`, this can help us analyze and compare performance changes later. There are intensive exams in these two weeks, and sometimes the response may be delayed. Thanks. -- ZheNing Hu ``` ## Christian Couder, 2021-07-05 19:09 Subject: Re: [GSoC] Git Blog 7 Message-ID: URL: https://gitlist.dev/e/CAP8UFD1_xjJxWA6O8Sx9-AEk5oC62U4GFkt5iRdx8Po_mJzTMg%40mail.gmail.com In-Reply-To: ``` On Sun, Jul 4, 2021 at 4:42 PM ZheNing Hu wrote: > > My seventh week blog finished: > The web version is here: > https://adlternative.github.io/GSOC-Git-Blog-7/ Thanks! > ## Week7 Performance Testing 2 > > This week I used performance flame graph at the suggestion of > my mentor `Christian` to find out where my patch affected the > performance of `cat-file --batch`. `oid_object_info_extended()` > takes the largest proportion of time, accounting for `90.28%` > and `41.60%` in `cat-file --batch` and `cat-file --batch-check` > respectively. Part of the reason is that `oid_object_info_extended()` > is called twice in `get_object()` with my patch. I tried to revise its > logic (`WIP`), the performance is improved when without using s/when without/when not/ > `--textconv` and `--filters`. > > `Ævar Arnfjörð Bjarmason` gave me a good suggestion on > performance regression: When we use the default format of > `git cat-file --batch-check` or `git cat-file --batch`, we can > directly print the meta-data of the object without going through > the logic of `ref-filter`; When we use other format, use the > logic in ref-filter. > > In addition, `Ævar Arnfjörð Bjarmason` also suggests adding a > performance test for `git cat-file --batch`, this can help us analyze > and compare performance changes later. > > There are intensive exams in these two weeks, and sometimes the > response may be delayed. Ok, no worries! ```