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fsmonitor: perpetual trivial response

Subject: fsmonitor: perpetual trivial response

## tl;dr

4 messages between Jul 27, 2022 and Aug 2, 2022.

replies: 3people: 3as markdown or json

Eric D· Jul 27, 2022, 20:03 UTC · lore

fsmonitor daemon was started in the background (i.e. git fsmonitor--daemon start) so I could enable trace2 logging.

15:36:37.860862 ...n/fsmonitor--daemon.c:969 | d1 | th01:ipc-server
      | region_enter | r1  | 124.965540 |           | fsmonitor    |
label:handle_client
15:36:37.860862 ...n/fsmonitor--daemon.c:970 | d1 | th01:ipc-server
      | data         | r1  | 124.965809 |  0.000269 | fsmonitor    |
..request:1658950597810367000
15:36:37.860862 ...n/fsmonitor--daemon.c:786 | d1 | th01:ipc-server
      | data         | r1  | 124.965892 |  0.000352 | fsmonitor    |
..response/token:builtin:0.12336.20220727T193432.938608Z:0
15:36:37.860862 ...n/fsmonitor--daemon.c:822 | d1 | th01:ipc-server
      | data         | r1  | 124.965969 |  0.000429 | fsmonitor    |
..response/trivial:1
15:36:37.860862 ...n/fsmonitor--daemon.c:974 | d1 | th01:ipc-server
      | region_leave | r1  | 124.966000 |  0.000460 | fsmonitor    |
label:handle_client
15:38:40.079662 ...n/fsmonitor--daemon.c:969 | d1 | th02:ipc-server
      | region_enter | r1  | 247.186960 |           | fsmonitor    |
label:handle_client
15:38:40.079662 ...n/fsmonitor--daemon.c:970 | d1 | th02:ipc-server
      | data         | r1  | 247.187067 |  0.000107 | fsmonitor    |
..request:1658950720017776200
15:38:40.079662 ...n/fsmonitor--daemon.c:786 | d1 | th02:ipc-server
      | data         | r1  | 247.187328 |  0.000368 | fsmonitor    |
..response/token:builtin:0.12336.20220727T193432.938608Z:0
15:38:40.079662 ...n/fsmonitor--daemon.c:822 | d1 | th02:ipc-server
      | data         | r1  | 247.187448 |  0.000488 | fsmonitor    |
..response/trivial:1
15:38:40.079662 ...n/fsmonitor--daemon.c:974 | d1 | th02:ipc-server
      | region_leave | r1  | 247.187491 |  0.000531 | fsmonitor    |
label:handle_client
15:42:14.719673 ...n/fsmonitor--daemon.c:969 | d1 | th03:ipc-server
      | region_enter | r1  | 461.821373 |           | fsmonitor    |
label:handle_client
15:42:14.719673 ...n/fsmonitor--daemon.c:970 | d1 | th03:ipc-server
      | data         | r1  | 461.821429 |  0.000056 | fsmonitor    |
..request:1658950934652816400
15:42:14.719673 ...n/fsmonitor--daemon.c:786 | d1 | th03:ipc-server
      | data         | r1  | 461.821467 |  0.000094 | fsmonitor    |
..response/token:builtin:0.12336.20220727T193432.938608Z:0
15:42:14.719673 ...n/fsmonitor--daemon.c:822 | d1 | th03:ipc-server
      | data         | r1  | 461.821486 |  0.000113 | fsmonitor    |
..response/trivial:1
15:42:14.719673 ...n/fsmonitor--daemon.c:974 | d1 | th03:ipc-server
      | region_leave | r1  | 461.821497 |  0.000124 | fsmonitor    |
label:handle_client

Note that this is a slightly hacked build of mine where I disabled the check for network filesystems. I also added some additional logging that tells me that the query is successful, it's just that the response is trivial. The sandbox I am using is on the network and being accessed from my Windows VM.

-Eric

Johannes Schindelin· Jul 28, 2022, 13:48 UTC · re: Eric D · lore

Re: fsmonitor: perpetual trivial response

Hi Eric,

On Wed, 27 Jul 2022, Eric D wrote:

Show 54 quoted lines

> fsmonitor daemon was started in the background (i.e. git
> fsmonitor--daemon start) so I could enable trace2 logging.
>
> 15:36:37.860862 ...n/fsmonitor--daemon.c:969 | d1 | th01:ipc-server
>       | region_enter | r1  | 124.965540 |           | fsmonitor    |
> label:handle_client
> 15:36:37.860862 ...n/fsmonitor--daemon.c:970 | d1 | th01:ipc-server
>       | data         | r1  | 124.965809 |  0.000269 | fsmonitor    |
> ..request:1658950597810367000
> 15:36:37.860862 ...n/fsmonitor--daemon.c:786 | d1 | th01:ipc-server
>       | data         | r1  | 124.965892 |  0.000352 | fsmonitor    |
> ..response/token:builtin:0.12336.20220727T193432.938608Z:0
> 15:36:37.860862 ...n/fsmonitor--daemon.c:822 | d1 | th01:ipc-server
>       | data         | r1  | 124.965969 |  0.000429 | fsmonitor    |
> ..response/trivial:1
> 15:36:37.860862 ...n/fsmonitor--daemon.c:974 | d1 | th01:ipc-server
>       | region_leave | r1  | 124.966000 |  0.000460 | fsmonitor    |
> label:handle_client
> 15:38:40.079662 ...n/fsmonitor--daemon.c:969 | d1 | th02:ipc-server
>       | region_enter | r1  | 247.186960 |           | fsmonitor    |
> label:handle_client
> 15:38:40.079662 ...n/fsmonitor--daemon.c:970 | d1 | th02:ipc-server
>       | data         | r1  | 247.187067 |  0.000107 | fsmonitor    |
> ..request:1658950720017776200
> 15:38:40.079662 ...n/fsmonitor--daemon.c:786 | d1 | th02:ipc-server
>       | data         | r1  | 247.187328 |  0.000368 | fsmonitor    |
> ..response/token:builtin:0.12336.20220727T193432.938608Z:0
> 15:38:40.079662 ...n/fsmonitor--daemon.c:822 | d1 | th02:ipc-server
>       | data         | r1  | 247.187448 |  0.000488 | fsmonitor    |
> ..response/trivial:1
> 15:38:40.079662 ...n/fsmonitor--daemon.c:974 | d1 | th02:ipc-server
>       | region_leave | r1  | 247.187491 |  0.000531 | fsmonitor    |
> label:handle_client
> 15:42:14.719673 ...n/fsmonitor--daemon.c:969 | d1 | th03:ipc-server
>       | region_enter | r1  | 461.821373 |           | fsmonitor    |
> label:handle_client
> 15:42:14.719673 ...n/fsmonitor--daemon.c:970 | d1 | th03:ipc-server
>       | data         | r1  | 461.821429 |  0.000056 | fsmonitor    |
> ..request:1658950934652816400
> 15:42:14.719673 ...n/fsmonitor--daemon.c:786 | d1 | th03:ipc-server
>       | data         | r1  | 461.821467 |  0.000094 | fsmonitor    |
> ..response/token:builtin:0.12336.20220727T193432.938608Z:0
> 15:42:14.719673 ...n/fsmonitor--daemon.c:822 | d1 | th03:ipc-server
>       | data         | r1  | 461.821486 |  0.000113 | fsmonitor    |
> ..response/trivial:1
> 15:42:14.719673 ...n/fsmonitor--daemon.c:974 | d1 | th03:ipc-server
>       | region_leave | r1  | 461.821497 |  0.000124 | fsmonitor    |
> label:handle_client
>
> Note that this is a slightly hacked build of mine where I disabled the
> check for network filesystems. I also added some additional logging
> that tells me that the query is successful, it's just that the
> response is trivial. The sandbox I am using is on the network and
> being accessed from my Windows VM.

Since you already "hacked" it, why not instrument it a bit more, e.g. offering some trace2 message for all the places where `do_trivial` is set to 1 in builtin/fsmonitor--daemon.c?

Or maybe you need to use `GIT_TRACE2_EVENT` instead of `GIT_TRACE2_PERF` (I vaguely remember that `error()` messages are only logged in one of these two modes).

Ciao, Johannes

Eric D· Aug 1, 2022, 18:19 UTC · re: Johannes Schindelin · lore

Re: fsmonitor: perpetual trivial response

On Thu, Jul 28, 2022 at 9:48 AM Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:

Show 70 quoted lines

>
> Hi Eric,
>
> On Wed, 27 Jul 2022, Eric D wrote:
>
> > fsmonitor daemon was started in the background (i.e. git
> > fsmonitor--daemon start) so I could enable trace2 logging.
> >
> > 15:36:37.860862 ...n/fsmonitor--daemon.c:969 | d1 | th01:ipc-server
> >       | region_enter | r1  | 124.965540 |           | fsmonitor    |
> > label:handle_client
> > 15:36:37.860862 ...n/fsmonitor--daemon.c:970 | d1 | th01:ipc-server
> >       | data         | r1  | 124.965809 |  0.000269 | fsmonitor    |
> > ..request:1658950597810367000
> > 15:36:37.860862 ...n/fsmonitor--daemon.c:786 | d1 | th01:ipc-server
> >       | data         | r1  | 124.965892 |  0.000352 | fsmonitor    |
> > ..response/token:builtin:0.12336.20220727T193432.938608Z:0
> > 15:36:37.860862 ...n/fsmonitor--daemon.c:822 | d1 | th01:ipc-server
> >       | data         | r1  | 124.965969 |  0.000429 | fsmonitor    |
> > ..response/trivial:1
> > 15:36:37.860862 ...n/fsmonitor--daemon.c:974 | d1 | th01:ipc-server
> >       | region_leave | r1  | 124.966000 |  0.000460 | fsmonitor    |
> > label:handle_client
> > 15:38:40.079662 ...n/fsmonitor--daemon.c:969 | d1 | th02:ipc-server
> >       | region_enter | r1  | 247.186960 |           | fsmonitor    |
> > label:handle_client
> > 15:38:40.079662 ...n/fsmonitor--daemon.c:970 | d1 | th02:ipc-server
> >       | data         | r1  | 247.187067 |  0.000107 | fsmonitor    |
> > ..request:1658950720017776200
> > 15:38:40.079662 ...n/fsmonitor--daemon.c:786 | d1 | th02:ipc-server
> >       | data         | r1  | 247.187328 |  0.000368 | fsmonitor    |
> > ..response/token:builtin:0.12336.20220727T193432.938608Z:0
> > 15:38:40.079662 ...n/fsmonitor--daemon.c:822 | d1 | th02:ipc-server
> >       | data         | r1  | 247.187448 |  0.000488 | fsmonitor    |
> > ..response/trivial:1
> > 15:38:40.079662 ...n/fsmonitor--daemon.c:974 | d1 | th02:ipc-server
> >       | region_leave | r1  | 247.187491 |  0.000531 | fsmonitor    |
> > label:handle_client
> > 15:42:14.719673 ...n/fsmonitor--daemon.c:969 | d1 | th03:ipc-server
> >       | region_enter | r1  | 461.821373 |           | fsmonitor    |
> > label:handle_client
> > 15:42:14.719673 ...n/fsmonitor--daemon.c:970 | d1 | th03:ipc-server
> >       | data         | r1  | 461.821429 |  0.000056 | fsmonitor    |
> > ..request:1658950934652816400
> > 15:42:14.719673 ...n/fsmonitor--daemon.c:786 | d1 | th03:ipc-server
> >       | data         | r1  | 461.821467 |  0.000094 | fsmonitor    |
> > ..response/token:builtin:0.12336.20220727T193432.938608Z:0
> > 15:42:14.719673 ...n/fsmonitor--daemon.c:822 | d1 | th03:ipc-server
> >       | data         | r1  | 461.821486 |  0.000113 | fsmonitor    |
> > ..response/trivial:1
> > 15:42:14.719673 ...n/fsmonitor--daemon.c:974 | d1 | th03:ipc-server
> >       | region_leave | r1  | 461.821497 |  0.000124 | fsmonitor    |
> > label:handle_client
> >
> > Note that this is a slightly hacked build of mine where I disabled the
> > check for network filesystems. I also added some additional logging
> > that tells me that the query is successful, it's just that the
> > response is trivial. The sandbox I am using is on the network and
> > being accessed from my Windows VM.
>
> Since you already "hacked" it, why not instrument it a bit more, e.g.
> offering some trace2 message for all the places where `do_trivial` is set
> to 1 in builtin/fsmonitor--daemon.c?
>
> Or maybe you need to use `GIT_TRACE2_EVENT` instead of `GIT_TRACE2_PERF`
> (I vaguely remember that `error()` messages are only logged in one of
> these two modes).
>
> Ciao,
> Johannes

My sandbox is sparse, but it is not "cone compliant"; temporarily disabling sparse checkout seems to have (temporarily) resolved this issue - at least for my purposes of testing fsmonitor out on network filesystems.

-Eric

Jeff Hostetler· Aug 2, 2022, 13:51 UTC · re: Eric D · lore

Re: fsmonitor: perpetual trivial response

On 8/1/22 2:19 PM, Eric D wrote:

Show 80 quoted lines

> On Thu, Jul 28, 2022 at 9:48 AM Johannes Schindelin
> <Johannes.Schindelin@gmx.de> wrote:
>>
>> Hi Eric,
>>
>> On Wed, 27 Jul 2022, Eric D wrote:
>>
>>> fsmonitor daemon was started in the background (i.e. git
>>> fsmonitor--daemon start) so I could enable trace2 logging.
>>>
>>> 15:36:37.860862 ...n/fsmonitor--daemon.c:969 | d1 | th01:ipc-server
>>>        | region_enter | r1  | 124.965540 |           | fsmonitor    |
>>> label:handle_client
>>> 15:36:37.860862 ...n/fsmonitor--daemon.c:970 | d1 | th01:ipc-server
>>>        | data         | r1  | 124.965809 |  0.000269 | fsmonitor    |
>>> ..request:1658950597810367000
>>> 15:36:37.860862 ...n/fsmonitor--daemon.c:786 | d1 | th01:ipc-server
>>>        | data         | r1  | 124.965892 |  0.000352 | fsmonitor    |
>>> ..response/token:builtin:0.12336.20220727T193432.938608Z:0
>>> 15:36:37.860862 ...n/fsmonitor--daemon.c:822 | d1 | th01:ipc-server
>>>        | data         | r1  | 124.965969 |  0.000429 | fsmonitor    |
>>> ..response/trivial:1
>>> 15:36:37.860862 ...n/fsmonitor--daemon.c:974 | d1 | th01:ipc-server
>>>        | region_leave | r1  | 124.966000 |  0.000460 | fsmonitor    |
>>> label:handle_client
>>> 15:38:40.079662 ...n/fsmonitor--daemon.c:969 | d1 | th02:ipc-server
>>>        | region_enter | r1  | 247.186960 |           | fsmonitor    |
>>> label:handle_client
>>> 15:38:40.079662 ...n/fsmonitor--daemon.c:970 | d1 | th02:ipc-server
>>>        | data         | r1  | 247.187067 |  0.000107 | fsmonitor    |
>>> ..request:1658950720017776200
>>> 15:38:40.079662 ...n/fsmonitor--daemon.c:786 | d1 | th02:ipc-server
>>>        | data         | r1  | 247.187328 |  0.000368 | fsmonitor    |
>>> ..response/token:builtin:0.12336.20220727T193432.938608Z:0
>>> 15:38:40.079662 ...n/fsmonitor--daemon.c:822 | d1 | th02:ipc-server
>>>        | data         | r1  | 247.187448 |  0.000488 | fsmonitor    |
>>> ..response/trivial:1
>>> 15:38:40.079662 ...n/fsmonitor--daemon.c:974 | d1 | th02:ipc-server
>>>        | region_leave | r1  | 247.187491 |  0.000531 | fsmonitor    |
>>> label:handle_client
>>> 15:42:14.719673 ...n/fsmonitor--daemon.c:969 | d1 | th03:ipc-server
>>>        | region_enter | r1  | 461.821373 |           | fsmonitor    |
>>> label:handle_client
>>> 15:42:14.719673 ...n/fsmonitor--daemon.c:970 | d1 | th03:ipc-server
>>>        | data         | r1  | 461.821429 |  0.000056 | fsmonitor    |
>>> ..request:1658950934652816400
>>> 15:42:14.719673 ...n/fsmonitor--daemon.c:786 | d1 | th03:ipc-server
>>>        | data         | r1  | 461.821467 |  0.000094 | fsmonitor    |
>>> ..response/token:builtin:0.12336.20220727T193432.938608Z:0
>>> 15:42:14.719673 ...n/fsmonitor--daemon.c:822 | d1 | th03:ipc-server
>>>        | data         | r1  | 461.821486 |  0.000113 | fsmonitor    |
>>> ..response/trivial:1
>>> 15:42:14.719673 ...n/fsmonitor--daemon.c:974 | d1 | th03:ipc-server
>>>        | region_leave | r1  | 461.821497 |  0.000124 | fsmonitor    |
>>> label:handle_client
>>>
>>> Note that this is a slightly hacked build of mine where I disabled the
>>> check for network filesystems. I also added some additional logging
>>> that tells me that the query is successful, it's just that the
>>> response is trivial. The sandbox I am using is on the network and
>>> being accessed from my Windows VM.
>>
>> Since you already "hacked" it, why not instrument it a bit more, e.g.
>> offering some trace2 message for all the places where `do_trivial` is set
>> to 1 in builtin/fsmonitor--daemon.c?
>>
>> Or maybe you need to use `GIT_TRACE2_EVENT` instead of `GIT_TRACE2_PERF`
>> (I vaguely remember that `error()` messages are only logged in one of
>> these two modes).
>>
>> Ciao,
>> Johannes
> 
> My sandbox is sparse, but it is not "cone compliant"; temporarily
> disabling sparse checkout seems to have (temporarily) resolved this
> issue - at least for my purposes of testing fsmonitor out on network
> filesystems.
> 
> -Eric
>

The first time status runs and it starts the daemon, you'll get a trivial response (because the daemon doesn't have a sync point established with client commands yet).

Subsequent client commands (like status) will continue to receive a trivial response *UNTIL* one of them updates the index and records the sync point (token) into the index. That is, until the index is updated with a valid token, they will continue to send not-sync'd timestamp in the request header and get a trivial response.

 > ..request:1658950934652816400
 >
 > ..response/token:builtin:0.12336.20220727T193432.938608Z:0
 > ..response/trivial:1

When/if any of these client commands update the the index, they will write the response token to the FSM index extension, and subsequent requests will send it to the daemon. The daemon will then start sending non-trivial responses (possibly with an updated token).

 > ..request:builtin:0.12336.20220727T193432.938608Z:0
 >
 > ..response/token:builtin:0.12336.20220727T193432.938608Z:1

Commands like `git status` may be read-only or may update the `lstat` times in cache-entries and rewrite the index. It is not always clear when a status command will and will not rewrite the index -- it just depends on what kind of changes it sees and how many. My point is that it will not update the token unless it updates the index, so you need to watch for that on the client side rather than looking at the daemon log.

Hope this helps, Jeff