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From: Mark Wielaard <mark@klomp.org>
To: Milian Wolff <mail@milianw.de>
Cc: "Frank Ch. Eigler" <fche@redhat.com>, elfutils-devel@sourceware.org
Subject: Re: caching failed lookups of debuginfo?
Date: Fri, 8 Apr 2022 22:59:55 +0200	[thread overview]
Message-ID: <YlCiS5wJMlXWopjw@wildebeest.org> (raw)
In-Reply-To: <2854938.4GpPBkblLQ@milian-workstation>

Hi Milian,

On Fri, Apr 08, 2022 at 10:45:10PM +0200, Milian Wolff wrote:
> In the off-CPU flame graphs I clearly see this callchain when DEBUGINFOD_URLS 
> is set:
> 
> ```
> dwfl_standard_find_debuginfo > debuginfod_query_server > curl_multi_wait
> ```
> 
> This accounts for ~2.5s of off-CPU time in my case. If you are saying that 
> negative lookups are cached, then what is this? Why would a second run of the 
> same dwfl-using application with the same input data keep querying the server?

That is certainly not what should happen once the cache is filled.
Could you run with DEBUGINFOD_VERBOSE=1 to see what is being fetched and why?

Thanks,

Mark


  reply	other threads:[~2022-04-08 20:59 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-08 19:58 Milian Wolff
2022-04-08 20:05 ` Frank Ch. Eigler
2022-04-08 20:45   ` Milian Wolff
2022-04-08 20:59     ` Mark Wielaard [this message]
2022-04-08 21:08       ` Milian Wolff
2022-04-08 21:34         ` Aaron Merey
2022-04-08 21:56           ` Milian Wolff
2022-04-08 22:21             ` Mark Wielaard
2022-04-08 22:23             ` Milian Wolff
2022-04-08 22:40               ` Mark Wielaard
2022-04-08 22:54                 ` Aaron Merey

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