From: David Smith <dsmith@redhat.com>
To: Felix Lu <flu@redhat.com>
Cc: systemtap@sourceware.org
Subject: Re: Writing tapset functions for multiple versions
Date: Wed, 20 Jul 2016 15:04:00 -0000 [thread overview]
Message-ID: <2000cfc0-9b01-e61d-23a8-bcded4c78be4@redhat.com> (raw)
In-Reply-To: <28211526.23172955.1469026042792.JavaMail.zimbra@redhat.com>
On 07/20/2016 09:47 AM, Felix Lu wrote:
>> Are there other ways to lower the overhead? Could each probe set a
>> global indexed by tid() to some value? (Or by that point would the
>> string comparison you are using be about the same?)
>
> A global integer instead of the string comparison could be set if you
> are worried about the overhead. In the example above, tid() could be
> saved in the probe alias body as a private global which would be sufficient
> for identifying the desired function.
I'm not quite sure how saving tid() in a private global would work if
you are probing more than one thread at a time. Or did I misunderstand
your idea and your global is an array? If the private global is an
array, now we've got 2 private global arrays (1 for version1.stp and 1
for version2.stp).
--
David Smith
dsmith@redhat.com
Red Hat
http://www.redhat.com
256.217.0141 (direct)
256.837.0057 (fax)
next prev parent reply other threads:[~2016-07-20 15:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <64396010.22700492.1468961291108.JavaMail.zimbra@redhat.com>
2016-07-19 21:06 ` Felix Lu
2016-07-20 14:05 ` David Smith
2016-07-20 14:47 ` Felix Lu
2016-07-20 15:04 ` David Smith [this message]
2016-07-20 15:25 ` Felix Lu
2016-07-20 16:23 ` Felix Lu
2016-07-20 16:38 ` Josh Stone
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