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Bug #524

closed

Decide an appropriate subbuffer size for per-uid UST buffers

Added by Mathieu Desnoyers over 8 years ago. Updated over 8 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
-
Target version:
Start date:
05/07/2013
Due date:
% Done:

100%

Estimated time:

Description

Currently, per-uid buffers use the same default subbuffer size as per-pid buffers, but it does not make sense to use this value, since the reason for having small per-pid buffers (that we have typically many pids in a system) does not apply to per-uid buffers.

Actions #1

Updated by David Goulet over 8 years ago

  • Status changed from New to Confirmed

Any suggestions ?

It depends on so much "unknown" variables such as the throughput, number of apps, number of events, ...

We can go 4 or 8 times bigger? Tbh, either a wild guest or we do a survey to our users. :)

Actions #2

Updated by Mathieu Desnoyers over 8 years ago

I'm tempted to derive the size based on the values we use for kernel tracing, and divide that value e.g. by 2, assuming we can have typically up to 2 users tracing in a system.

Thoughts ?

Thanks,

Mathieu

Actions #3

Updated by Anonymous over 8 years ago

Mathieu Desnoyers wrote:

I'm tempted to derive the size based on the values we use for kernel tracing, and divide that value e.g. by 2, assuming we can have typically up to 2 users tracing in a system.

This would make sense for defining the default value. However, would it be a separate entry in defaults.h?

Actions #4

Updated by Mathieu Desnoyers over 8 years ago

Yes, we'd split the current UST default entries into UST_PID and
UST_UID.

Thanks,

Mathieu

--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

Actions #5

Updated by David Goulet over 8 years ago

Yah most probably it will be a default value specific to per UID buffers.

So the Kernel size is: 262144 bytes so dividing this by two makes: 131072 bytes --> 128K

Seems good as any other values to me :)

Actions #6

Updated by David Goulet over 8 years ago

  • Status changed from Confirmed to Resolved
  • % Done changed from 0 to 100
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