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From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Jeff Hostetler <git@jeffhostetler.com>
Cc: Jeff Hostetler via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, jeffhost@microsoft.com,
	Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v6 00/15] Trace2 tracing facility
Date: Sun, 17 Mar 2019 15:22:49 +0100	[thread overview]
Message-ID: <87k1gxa8cm.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <0aff8302-371e-cb5e-fe5e-f08e45456559@jeffhostetler.com>


On Fri, Feb 15 2019, Jeff Hostetler wrote:

> On 2/14/2019 7:33 AM, Ævar Arnfjörð Bjarmason wrote:
>>
>> On Wed, Feb 06 2019, Jeff Hostetler via GitGitGadget wrote:
>>
>>> V6 addresses: [] The remaining hdr-check warning in trace2/tr2_tls.h
>>>
>>> There are no other outstanding comments that I'm aware of.
>>
>> Not a comment on this, just a follow-up question. I started looking into
>> whether this could be driven by config instead of getenv(). A lot easier
>> to set up in some cases than injecting env variables, especialy if the
>> log target supported a strftime() string, is any of that something
>> you've looked into already (so I don't do dupe work...).
>>
>> There's the chicken & egg problem with wanting to do traces way before
>> we get to reading config, so I expect that such a facility would need to
>> work by always trace record at the beginning until we get far enough to
>> write the config, and then either stop and throw away the buffer, or
>> write out the existing trace to the configured target, and continue.
>>
>
> Yes, I beat my head against the config settings for quite a while
> before settling on using an env var.
>
> I wanted to get the:
> () full process elapsed time,
> () the full original argv,
> () all of the command dispatch, run-dashed, and alias expansion,
> () and for my atexit() to run last.
> So I hooked into main() before the config is loaded.
>
> In most commands, the config is processed about the same time as
> parse_options() is called.  And we have to insert code in
> git_default_config() to load my settings.  This happens after all
> of the .git dir discovery, "-c" and "-C" processing, alias expansion,
> command dispatch and etc.  And the argv received in the cmd_*()
> function has been modified.  So we lose some information.  (I tried
> this for a while and didn't like the results.)
>
> I also tried using read_early_config() various places, but there
> were problems here too.  Too early and the "-c" settings weren't
> parsed yet.  And there was an issue about when .git dir was discovered,
> so local config settings weren't ready yet.
>
> I also recall having a problem when doing an early iteration with
> side effects (or rather the early iteration caused something to be
> set that caused the real iteration (in cmd_*()) to short-cut), but
> I don't remember the details.
>
> So we have a custom installer that also sets the environment variable
> after git is installed and haven't had any problems.
>
>
> I hesitate to say we should always start allocating a bunch of data
> and spinning up the TLS data and etc. before we know if tracing is
> wanted.  Just seems expensive for most users.
>
>
> I could see having a "~/.git_tr2_config" or something similar in
> some place like "/etc" that only contained the Trace2 settings.
> It would be safe to read very early inside main() and we would not
> consider it to be part of the real config.  For example, "git config"
> would not know about it.  Then you could enforce a system-wide
> setting without any of the env var issues.

I haven't written a patch for this, but it seems to me that we could
just start reading /etc/gitconfig via some custom config callback code
early as e.g. 58b284a2e91 ("worktree: add per-worktree config files",
2018-10-21) does for the worktree config.

It would ignore everything except trace.* or wherever namespace we'll
put this in, and "-c" etc. wouldn't work. We could just document that as
a limitation for now which could be fixed later.

It wouldn't make things worse, and would mean you could easily set
logging system-wide without needing to inject environment variables in
lots of custom (and sometimes hard-to-do) places, which I expect is the
most common use-case, and is the one I have.

> WRT the strftime() question, we could either add syntax to the
> env var value (or the tr2 config setting) to have some tokens
> for that.  I just stuck with absolute pathnames since I started
> by copying what was done for GIT_TRACE.
>
> Jeff

  reply	other threads:[~2019-03-17 14:22 UTC|newest]

Thread overview: 154+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-22 21:22 [PATCH 00/14] Trace2 tracing facility Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 01/14] trace2: Documentation/technical/api-trace2.txt Jeff Hostetler via GitGitGadget
2019-01-23 20:51   ` Junio C Hamano
2019-01-25 21:13     ` Jeff Hostetler
2019-01-25 13:19   ` SZEDER Gábor
2019-01-25 17:53     ` Josh Steadmon
2019-01-22 21:22 ` [PATCH 02/14] trace2: create new combined trace facility Jeff Hostetler via GitGitGadget
2019-01-25 11:22   ` SZEDER Gábor
2019-01-25 19:13     ` Junio C Hamano
2019-01-22 21:22 ` [PATCH 04/14] trace2:data: add trace2 regions to wt-status Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 03/14] trace2: collect platform-specific process information Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 05/14] trace2:data: add editor/pager child classification Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 06/14] trace2:data: add trace2 sub-process classification Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 07/14] trace2:data: add trace2 transport child classification Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 09/14] trace2:data: add trace2 instrumentation to index read/write Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 08/14] trace2:data: add trace2 hook classification Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 10/14] pack-objects: add trace2 regions Derrick Stolee via GitGitGadget
2019-01-23  1:19   ` Derrick Stolee
2019-01-22 21:22 ` [PATCH 11/14] trace2:data: add subverb to checkout command Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 12/14] trace2:data: add subverb to reset command Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 13/14] trace2:data: add subverb for rebase Jeff Hostetler via GitGitGadget
2019-01-22 21:22 ` [PATCH 14/14] trace2: t/helper/test-trace2, t0210.sh, t0211.sh, t0212.sh Jeff Hostetler via GitGitGadget
2019-01-22 23:21 ` [PATCH 00/14] Trace2 tracing facility Junio C Hamano
2019-01-25 20:03 ` Josh Steadmon
2019-01-30 18:45   ` Jeff Hostetler
2019-01-28 16:15 ` Jeff Hostetler
2019-01-28 18:07   ` Junio C Hamano
2019-01-28 21:47 ` [PATCH v2 " Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 01/14] trace2: Documentation/technical/api-trace2.txt Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 02/14] trace2: create new combined trace facility Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 03/14] trace2: collect platform-specific process information Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 04/14] trace2:data: add trace2 regions to wt-status Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 05/14] trace2:data: add editor/pager child classification Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 06/14] trace2:data: add trace2 sub-process classification Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 07/14] trace2:data: add trace2 transport child classification Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 08/14] trace2:data: add trace2 hook classification Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 09/14] trace2:data: add trace2 instrumentation to index read/write Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 10/14] pack-objects: add trace2 regions Derrick Stolee via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 11/14] trace2:data: add subverb to checkout command Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 12/14] trace2:data: add subverb to reset command Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 13/14] trace2:data: add subverb for rebase Jeff Hostetler via GitGitGadget
2019-01-28 21:47   ` [PATCH v2 14/14] trace2: t/helper/test-trace2, t0210.sh, t0211.sh, t0212.sh Jeff Hostetler via GitGitGadget
2019-01-28 22:23     ` Junio C Hamano
2019-01-29 22:08       ` Jeff Hostetler
2019-01-30 19:51   ` [PATCH v3 00/14] Trace2 tracing facility Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 01/14] trace2: Documentation/technical/api-trace2.txt Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 02/14] trace2: create new combined trace facility Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 04/14] trace2:data: add trace2 regions to wt-status Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 03/14] trace2: collect platform-specific process information Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 06/14] trace2:data: add trace2 sub-process classification Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 05/14] trace2:data: add editor/pager child classification Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 07/14] trace2:data: add trace2 transport " Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 08/14] trace2:data: add trace2 hook classification Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 09/14] trace2:data: add trace2 instrumentation to index read/write Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 10/14] pack-objects: add trace2 regions Derrick Stolee via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 12/14] trace2:data: add subverb to reset command Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 11/14] trace2:data: add subverb to checkout command Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 13/14] trace2:data: add subverb for rebase Jeff Hostetler via GitGitGadget
2019-01-30 19:51     ` [PATCH v3 14/14] trace2: t/helper/test-trace2, t0210.sh, t0211.sh, t0212.sh Jeff Hostetler via GitGitGadget
2019-01-30 20:56     ` [PATCH v4 00/14] Trace2 tracing facility Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 01/14] trace2: Documentation/technical/api-trace2.txt Jeff Hostetler via GitGitGadget
2019-01-31 14:11         ` SZEDER Gábor
2019-01-31 22:33           ` Jeff Hostetler
2019-01-31 23:39             ` Junio C Hamano
2019-01-30 20:56       ` [PATCH v4 02/14] trace2: create new combined trace facility Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 04/14] trace2:data: add trace2 regions to wt-status Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 03/14] trace2: collect platform-specific process information Jeff Hostetler via GitGitGadget
2019-01-31 23:15         ` SZEDER Gábor
2019-02-01 11:12           ` Jeff Hostetler
2019-01-30 20:56       ` [PATCH v4 05/14] trace2:data: add editor/pager child classification Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 06/14] trace2:data: add trace2 sub-process classification Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 07/14] trace2:data: add trace2 transport child classification Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 08/14] trace2:data: add trace2 hook classification Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 09/14] trace2:data: add trace2 instrumentation to index read/write Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 10/14] pack-objects: add trace2 regions Derrick Stolee via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 11/14] trace2:data: add subverb to checkout command Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 12/14] trace2:data: add subverb to reset command Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 13/14] trace2:data: add subverb for rebase Jeff Hostetler via GitGitGadget
2019-01-30 20:56       ` [PATCH v4 14/14] trace2: t/helper/test-trace2, t0210.sh, t0211.sh, t0212.sh Jeff Hostetler via GitGitGadget
2019-01-31 23:28         ` SZEDER Gábor
2019-01-31 23:41           ` Junio C Hamano
2019-02-01 11:08             ` Jeff Hostetler
2019-01-31 18:46       ` [PATCH v4 00/14] Trace2 tracing facility Junio C Hamano
2019-02-01 17:58       ` [PATCH v5 00/15] " Jeff Hostetler via GitGitGadget
2019-02-01 17:58         ` [PATCH v5 01/15] trace2: Documentation/technical/api-trace2.txt Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 02/15] trace2: create new combined trace facility Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 03/15] trace2: collect Windows-specific process information Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 05/15] trace2:data: add editor/pager child classification Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 04/15] trace2:data: add trace2 regions to wt-status Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 06/15] trace2:data: add trace2 sub-process classification Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 07/15] trace2:data: add trace2 transport child classification Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 08/15] trace2:data: add trace2 hook classification Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 09/15] trace2:data: add trace2 instrumentation to index read/write Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 10/15] trace2:data: pack-objects: add trace2 regions Derrick Stolee via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 11/15] trace2:data: add subverb to checkout command Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 12/15] trace2:data: add subverb to reset command Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 13/15] trace2:data: add subverb for rebase Jeff Hostetler via GitGitGadget
2019-02-01 17:59         ` [PATCH v5 14/15] trace2: t/helper/test-trace2, t0210.sh, t0211.sh, t0212.sh Jeff Hostetler via GitGitGadget
2019-02-13 13:15           ` Ævar Arnfjörð Bjarmason
2019-02-01 17:59         ` [PATCH v5 15/15] trace2: add for_each macros to clang-format Jeff Hostetler via GitGitGadget
2019-02-06 17:15         ` [PATCH v6 00/15] Trace2 tracing facility Jeff Hostetler via GitGitGadget
2019-02-06 17:15           ` [PATCH v6 01/15] trace2: Documentation/technical/api-trace2.txt Jeff Hostetler via GitGitGadget
2019-02-06 17:15           ` [PATCH v6 02/15] trace2: create new combined trace facility Jeff Hostetler via GitGitGadget
2019-02-15 16:00             ` Ævar Arnfjörð Bjarmason
2019-02-15 17:57               ` Jeff Hostetler
2019-02-06 17:15           ` [PATCH v6 03/15] trace2: collect Windows-specific process information Jeff Hostetler via GitGitGadget
2019-02-06 17:15           ` [PATCH v6 04/15] trace2:data: add trace2 regions to wt-status Jeff Hostetler via GitGitGadget
2019-02-06 17:15           ` [PATCH v6 05/15] trace2:data: add editor/pager child classification Jeff Hostetler via GitGitGadget
2019-02-06 17:15           ` [PATCH v6 06/15] trace2:data: add trace2 sub-process classification Jeff Hostetler via GitGitGadget
2019-02-06 17:15           ` [PATCH v6 07/15] trace2:data: add trace2 transport child classification Jeff Hostetler via GitGitGadget
2019-02-06 17:16           ` [PATCH v6 08/15] trace2:data: add trace2 hook classification Jeff Hostetler via GitGitGadget
2019-02-06 17:16           ` [PATCH v6 09/15] trace2:data: add trace2 instrumentation to index read/write Jeff Hostetler via GitGitGadget
2019-02-06 17:16           ` [PATCH v6 10/15] trace2:data: pack-objects: add trace2 regions Derrick Stolee via GitGitGadget
2019-02-06 17:16           ` [PATCH v6 11/15] trace2:data: add subverb to checkout command Jeff Hostetler via GitGitGadget
2019-02-06 17:16           ` [PATCH v6 12/15] trace2:data: add subverb to reset command Jeff Hostetler via GitGitGadget
2019-02-06 17:16           ` [PATCH v6 13/15] trace2:data: add subverb for rebase Jeff Hostetler via GitGitGadget
2019-02-06 17:16           ` [PATCH v6 14/15] trace2: t/helper/test-trace2, t0210.sh, t0211.sh, t0212.sh Jeff Hostetler via GitGitGadget
2019-02-06 17:16           ` [PATCH v6 15/15] trace2: add for_each macros to clang-format Jeff Hostetler via GitGitGadget
2019-02-14 12:33           ` [PATCH v6 00/15] Trace2 tracing facility Ævar Arnfjörð Bjarmason
2019-02-15 17:25             ` Jeff Hostetler
2019-03-17 14:22               ` Ævar Arnfjörð Bjarmason [this message]
2019-03-21 14:30                 ` Johannes Schindelin
2019-03-21 14:48                   ` Ævar Arnfjörð Bjarmason
2019-03-22 13:17                     ` Johannes Schindelin
2019-03-22 14:01                       ` Jeff Hostetler
2019-03-22 14:53                         ` Ævar Arnfjörð Bjarmason
2019-03-22 15:21                           ` Jeff Hostetler
2019-02-22 22:24           ` [PATCH v7 " Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 01/15] trace2: Documentation/technical/api-trace2.txt Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 02/15] trace2: create new combined trace facility Jeff Hostetler via GitGitGadget
2019-05-10 17:28               ` SZEDER Gábor
2019-05-10 19:54                 ` Derrick Stolee
2019-02-22 22:25             ` [PATCH v7 03/15] trace2: collect Windows-specific process information Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 04/15] trace2:data: add trace2 regions to wt-status Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 05/15] trace2:data: add editor/pager child classification Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 06/15] trace2:data: add trace2 sub-process classification Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 07/15] trace2:data: add trace2 transport child classification Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 08/15] trace2:data: add trace2 hook classification Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 10/15] trace2:data: pack-objects: add trace2 regions Derrick Stolee via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 09/15] trace2:data: add trace2 instrumentation to index read/write Jeff Hostetler via GitGitGadget
2019-05-10 13:37               ` [PATCH] trace2: fix up a missing "leave" entry point Ævar Arnfjörð Bjarmason
2019-05-10 13:45                 ` Derrick Stolee
2019-05-20 16:50                 ` Jeff Hostetler
2019-02-22 22:25             ` [PATCH v7 11/15] trace2:data: add subverb to checkout command Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 12/15] trace2:data: add subverb to reset command Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 14/15] trace2: t/helper/test-trace2, t0210.sh, t0211.sh, t0212.sh Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 13/15] trace2:data: add subverb for rebase Jeff Hostetler via GitGitGadget
2019-02-22 22:25             ` [PATCH v7 15/15] trace2: add for_each macros to clang-format Jeff Hostetler via GitGitGadget
2019-01-31 14:38     ` [PATCH v3 00/14] Trace2 tracing facility SZEDER Gábor
2019-01-31 14:53       ` Jeff Hostetler
2019-01-31 18:51         ` Junio C Hamano
2019-01-31 19:45           ` Jeff Hostetler
2019-01-31 22:11             ` Jeff Hostetler
2019-01-31 23:30               ` Junio C Hamano

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