Messages in this thread | | | Date | Thu, 25 Feb 2016 16:47:14 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH v6 0/8] Additional kmsg devices |
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Hello, Kazimierz.
On Wed, Feb 24, 2016 at 12:53:13PM +0100, Kazimierz Krosman wrote: > 1. kmsg device does not require maintenance by reader process side. > Multiple writers can write to a device and new records overwrite logs saved earlier. > When system crashes logs can be restored with pstore mechanism.
I'm not sure this is the right layer to implement generic logging facility.
> 2. Using kmsg can cause lower CPU utilisation in the real-word use case than > userspace logging mechanisms. > We created 2 tests: (1) 100 writer processes write to created kmsg buffer and > (2) 100 writers write to socket (stream)- there is one reader to protect > socket buffer against overflow. Tests show that cpu utilisation in case of first > test is about 2.3 times lower (39.1%) than it is in second case (87.7%) (measured > with top program; tests code is attached below). Tested on Odroid XU4.
This sounds like a generic IPC problem than anything else.
Thanks.
-- tejun
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