All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
To: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: "Thomas Huth" <thuth@redhat.com>,
	"Kyle Evans" <kevans@freebsd.org>,
	qemu-devel@nongnu.org,
	"Wainer dos Santos Moschetta" <wainersm@redhat.com>,
	"Willian Rampazzo" <willianr@redhat.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"Warner Losh" <imp@bsdimp.com>
Subject: Re: [PATCH v3 4/6] gitlab-ci: Add ccache in $PATH and display statistics
Date: Fri, 21 May 2021 16:21:07 +0200	[thread overview]
Message-ID: <c4910e92-359f-3517-fb7e-65cbbe8deb1a@amsat.org> (raw)
In-Reply-To: <YKes/fqDNT4G9jx/@redhat.com>

On 5/21/21 2:52 PM, Daniel P. Berrangé wrote:
> On Fri, May 21, 2021 at 02:27:26PM +0200, Philippe Mathieu-Daudé wrote:
>> On 5/21/21 1:53 PM, Daniel P. Berrangé wrote:
>>> On Fri, May 21, 2021 at 01:02:51PM +0200, Thomas Huth wrote:
>>>> On 21/05/2021 12.50, Daniel P. Berrangé wrote:
>>>>> On Fri, May 21, 2021 at 12:48:21PM +0200, Thomas Huth wrote:
>>>>>> On 20/05/2021 13.27, Philippe Mathieu-Daudé wrote:
>>>>>>> +Stefan/Daniel
>>>>>>>
>>>>>>> On 5/20/21 10:02 AM, Thomas Huth wrote:
>>>>>>>> On 19/05/2021 20.45, Philippe Mathieu-Daudé wrote:
>>>>>>>>> If a runner has ccache installed, use it and display statistics
>>>>>>>>> at the end of the build.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>>>>>>>>> ---
>>>>>>>>>     .gitlab-ci.d/buildtest-template.yml | 5 +++++
>>>>>>>>>     1 file changed, 5 insertions(+)
>>>>>>>>>
>>>>>>>>> diff --git a/.gitlab-ci.d/buildtest-template.yml
>>>>>>>>> b/.gitlab-ci.d/buildtest-template.yml
>>>>>>>>> index f284d7a0eec..a625c697d3b 100644
>>>>>>>>> --- a/.gitlab-ci.d/buildtest-template.yml
>>>>>>>>> +++ b/.gitlab-ci.d/buildtest-template.yml
>>>>>>>>> @@ -6,13 +6,18 @@
>>>>>>>>>           then
>>>>>>>>>             JOBS=$(sysctl -n hw.ncpu)
>>>>>>>>>             MAKE=gmake
>>>>>>>>> +        PATH=/usr/local/libexec/ccache:$PATH
>>>>>>>>>             ;
>>>>>>>>>           else
>>>>>>>>>             JOBS=$(expr $(nproc) + 1)
>>>>>>>>>             MAKE=make
>>>>>>>>> +        PATH=/usr/lib/ccache:/usr/lib64/ccache:$PATH
>>>>>>>>
>>>>>>>> That does not make sense for the shared runners yet. We first need
>>>>>>>> something to enable the caching there - see my series "Use ccache in the
>>>>>>>> gitlab-CI" from April (which is currently stalled unfortunately).
>>>>>>>
>>>>>>> TL;DR: I don't think we should restrict our templates to shared runners.
>>>>>>
>>>>>> I'm certainly not voting for restricting ourselves to only use shared
>>>>>> runners here - but my concern is that this actually *slows* down the shared
>>>>>> runners even more! (sorry, I should have elaborated on that in my previous
>>>>>> mail already)
>>>>>>
>>>>>> When I was experimenting with ccache in the shared runners, I saw that the
>>>>>> jobs are running even slower with ccache enabled as long as the cache is not
>>>>>> populated yet. You only get a speedup afterwards. So if you add this now
>>>>>> without also adding the possibility to store the cache persistently, the
>>>>>> shared runners will try to populate the cache each time just to throw away
>>>>>> the results afterwards again. Thus all the shared runners only get slower
>>>>>> without any real benefit here.
>>>>>>
>>>>>> Thus we either need to get ccache working properly for the shared runners
>>>>>> first, or you have to think of a different way of enabling ccache for the
>>>>>> non-shared runners, so that it does not affect the shared runners
>>>>>> negatively.
>>>>>
>>>>> Is there anything functional holding up your previous full cccache support
>>>>> series from last month ? Or is it just lack of reviews ?
>>>>
>>>> It's basically the problems mentioned in the cover letter and Stefan's
>>>> comment here:
>>>>
>>>>  https://lists.gnu.org/archive/html/qemu-devel/2021-04/msg02219.html
>>>
>>> I'm not sure I understand why Stefan thinks gitlab's caching doesn't
>>> benefit ccache. We add ccache for libvirt GitLab CI, and AFAIR it
>>> sped up our builds significantly.
>>
>> I think Stefan is referring to a comment I made, when using both
>> shared runners and dedicated runners (what I'm currently testing)
>> various jobs are stuck transferring artifacts/cache {FROM, TO}
>> {shared, dedicated} runners at the same time, which is sub-optimal
>> because it saturate the dedicated runner network link.
> 
> I think we're over thinking things a bit too much and worrying about
> scenarios that we're not actually hitting that frequently today, and
> delaying the benefit for everyone.
> 
> Our common case is that most contributors are simply using shared
> runners exclusively, as is the main qemu repo staging branch. AFAIK
> these should benefit from a simple ccache enablement today.
> 
> Since there are questions about other setups though, we can just
> provide an easy way to turn it off. eg:
> 
>   if test -z "$QEMU_CI_SKIP_CCACHE"
>   then
>      PATH=/usr/local/libexec/ccache:$PATH
>   fi
> 
> anyone who wishes to disable it, can just set that variable in their
> git repo fork. If there are specific jobs we want to disable cccache
> for, those jobs can set that too.

OK, understood. I'll see with Willian how to have ccache working.

Thanks for the feedback,

Phil.


  reply	other threads:[~2021-05-21 14:22 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-19 18:45 [PATCH v3 0/6] gitlab-ci: Allow using FreeBSD runners Philippe Mathieu-Daudé
2021-05-19 18:45 ` [PATCH v3 1/6] gitlab-ci: Extract &environment_variables template Philippe Mathieu-Daudé
2021-05-19 19:12   ` Willian Rampazzo
2021-05-20 18:00   ` Wainer dos Santos Moschetta
2021-05-19 18:45 ` [PATCH v3 2/6] gitlab-ci: Adapt JOBS variable for FreeBSD runners Philippe Mathieu-Daudé
2021-05-19 19:11   ` Willian Rampazzo
2021-05-20  5:50   ` Thomas Huth
2021-05-20 18:18   ` Wainer dos Santos Moschetta
2021-05-20 20:02     ` Warner Losh
2021-05-19 18:45 ` [PATCH v3 3/6] gitlab-ci: Run GNU make via the $MAKE variable Philippe Mathieu-Daudé
2021-05-19 19:10   ` Willian Rampazzo
2021-05-20  7:56   ` Thomas Huth
2021-05-20 18:26   ` Wainer dos Santos Moschetta
2021-05-19 18:45 ` [PATCH v3 4/6] gitlab-ci: Add ccache in $PATH and display statistics Philippe Mathieu-Daudé
2021-05-19 19:14   ` Willian Rampazzo
2021-05-20  8:02   ` Thomas Huth
2021-05-20 11:27     ` Philippe Mathieu-Daudé
2021-05-21 10:48       ` Thomas Huth
2021-05-21 10:50         ` Daniel P. Berrangé
2021-05-21 11:02           ` Thomas Huth
2021-05-21 11:53             ` Daniel P. Berrangé
2021-05-21 12:27               ` Philippe Mathieu-Daudé
2021-05-21 12:52                 ` Daniel P. Berrangé
2021-05-21 14:21                   ` Philippe Mathieu-Daudé [this message]
2021-05-25  5:49                     ` Philippe Mathieu-Daudé
2021-05-24 13:51                   ` Stefan Hajnoczi
2021-05-25  5:50                     ` Philippe Mathieu-Daudé
2021-05-21 12:36             ` Willian Rampazzo
2021-05-21 13:02               ` Thomas Huth
2021-05-19 18:45 ` [PATCH v3 5/6] gitlab-ci: Simplify before/after script for Avocado based jobs Philippe Mathieu-Daudé
2021-05-19 19:42   ` Willian Rampazzo
2021-05-20  8:04   ` Thomas Huth
2021-05-19 18:45 ` [PATCH v3 6/6] gitlab-ci: Add FreeBSD jobs Philippe Mathieu-Daudé
2021-05-19 19:43   ` Willian Rampazzo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=c4910e92-359f-3517-fb7e-65cbbe8deb1a@amsat.org \
    --to=f4bug@amsat.org \
    --cc=alex.bennee@linaro.org \
    --cc=berrange@redhat.com \
    --cc=imp@bsdimp.com \
    --cc=kevans@freebsd.org \
    --cc=qemu-devel@nongnu.org \
    --cc=stefanha@redhat.com \
    --cc=thuth@redhat.com \
    --cc=wainersm@redhat.com \
    --cc=willianr@redhat.com \
    --subject='Re: [PATCH v3 4/6] gitlab-ci: Add ccache in $PATH and display statistics' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.