From: Avi Kivity <avi@scylladb.com>
To: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Mark Wielaard <mjw@redhat.com>, David Smith <dsmith@redhat.com>,
systemtap@sourceware.org
Subject: Re: Some newbie questions
Date: Thu, 25 Aug 2016 16:21:00 -0000 [thread overview]
Message-ID: <c8c0f0b6-f8a7-7104-9faf-a30e89076e5f@scylladb.com> (raw)
In-Reply-To: <20160817183537.GB4647@redhat.com>
On 08/17/2016 09:35 PM, Frank Ch. Eigler wrote:
> Hi -
>
> On Wed, Aug 17, 2016 at 09:30:38PM +0300, Avi Kivity wrote:
>> [...]
>>>> My load indeed calls epoll_wait() at a high rate, with zero timeout.
>>> [...]
>> Yes. It's not very common, but some high throughput or latency
>> sensitive applications will poll. In my case it's both high throughput
>> and latency sensitive.
> Interesting. I assume you've measured that.
>
>
>> [...]
>>> looks for mmap/exec syscalls. Perhaps there could be a mode (a -D
>>> setting?) for selecting kprobes rather than syscall-tracepoints to
>>> catch those events.
>> Why not trace just mmap and exec syscalls, rather than everything?
>> Surely there's a static tracepoint for those.
> Heh, in this case it's "surely not". :-) There exists only a
> multiplexed system-call-entry and a system-call-exit pair of
> tracepoints.
>
Hi,
Should I wait for ongoing improvement here, or shall I look elsewhere
for my tracing needs?
It would be a pity (for me) if I have to find another solution, because
systemtap has all the expressiveness and integration I need. But it has
a dramatic impact on my application runtime.
I was able to extract some useful data with perf probe/perf record, but
as soon as I need to qualify a probe point with runtime information,
perf falls short.
Avi
next prev parent reply other threads:[~2016-08-25 16:21 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-07 8:08 Avi Kivity
2016-08-07 9:16 ` Avi Kivity
2016-08-08 14:58 ` David Smith
2016-08-09 6:51 ` Avi Kivity
2016-08-09 13:54 ` Mark Wielaard
2016-08-09 14:11 ` Avi Kivity
2016-08-10 15:33 ` Frank Ch. Eigler
2016-08-10 15:39 ` Avi Kivity
2016-08-10 15:40 ` Avi Kivity
2016-08-10 16:47 ` Frank Ch. Eigler
2016-08-11 7:51 ` Avi Kivity
2016-08-11 8:13 ` Avi Kivity
2016-08-11 16:18 ` Frank Ch. Eigler
2016-08-17 15:15 ` Avi Kivity
2016-08-17 18:06 ` David Smith
2016-08-17 18:22 ` Avi Kivity
2016-08-17 18:10 ` Frank Ch. Eigler
2016-08-17 18:30 ` Avi Kivity
2016-08-17 18:35 ` Frank Ch. Eigler
2016-08-17 18:42 ` Avi Kivity
2016-08-25 16:21 ` Avi Kivity [this message]
2016-08-25 17:37 ` David Smith
2016-08-26 18:39 ` Avi Kivity
2016-08-26 20:08 ` David Smith
2016-08-26 21:21 ` Josh Stone
2016-08-28 13:30 ` Avi Kivity
2016-08-28 13:35 ` Avi Kivity
2016-08-28 13:45 ` Avi Kivity
2016-08-29 18:26 ` David Smith
2016-08-31 16:44 ` Avi Kivity
2016-08-09 15:17 ` David Smith
2016-08-09 15:28 ` Avi Kivity
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