Elad Lahav
Sent: Friday, October 03, 2008 11:22 AM
To: Steve Sistare
Cc: perf-discuss@opensolaris.org
Subject: Re: [perf-discuss] Idle time numbers for a T1 strand
Thanks, Steve, but the blog does not answer my question.
With vmstat reporting 50% idle time, and the core greatly under-utilised
(about
On 10/03/08 13:20, Elad Lahav wrote:
>> (In your first posting you said mpstat was used, not vmstat, so
>> I will assume mpstat).
> Oops, of course, I meant mpstat...
>
>> If mpstat shows idle time, then during the idle time, no thread
>> is runnable from a high-level, traditional operating system
> (In your first posting you said mpstat was used, not vmstat, so
> I will assume mpstat).
Oops, of course, I meant mpstat...
> If mpstat shows idle time, then during the idle time, no thread
> is runnable from a high-level, traditional operating system point
> of view.
Not sure about that. mpstat
mpstat's view is at the operating system level. The OS has assigned a
thread to run on the core. The OS doesn't care whether that thread
spends its time quanta trying to issue an instruction every cycle, or
stalled waiting for memory. Either way the OS cannot assign another
software thread to t
(In your first posting you said mpstat was used, not vmstat, so
I will assume mpstat).
mpstat shows the percent of time that threads spend running on the
CPU, where each CPU is a hardware strand, and 4 strands share an
instruction pipeline. At the lowest level, some of this time is
spent executin
Thanks, Steve, but the blog does not answer my question.
With vmstat reporting 50% idle time, and the core greatly under-utilised (about
25%), how
do you determine that a *single thread* has reached its limit? I would expect
0% idle time
on vmstat in that case.
The main issue is that the number
Correction in-line...
David Collier-Brown wrote:
> Elad Lahav <[EMAIL PROTECTED]> asjed
> | I'm looking into the performance of a simple, single-threaded, TCP
> server on a T1000.
> | According to mpstat, the strand running the server is about 50% idle.
> However, performance
> | counters sugges
Elad Lahav <[EMAIL PROTECTED]> asjed
| I'm looking into the performance of a simple, single-threaded, TCP server on
a T1000.
| According to mpstat, the strand running the server is about 50% idle.
However, performance
| counters suggest that it is executing about 230 million instructions per
sec
See Ravi Talashikar's blog for an explanation of CPU vs core
utilization on CMT architectures such as the T1000:
http://blogs.sun.com/travi/entry/ultrasparc_t1_utilization_explained
- Steve
On 09/30/08 15:18, Elad Lahav wrote:
> I'm looking into the performance of a simple, single-threaded, TC
I'm looking into the performance of a simple, single-threaded, TCP server on a
T1000.
According to mpstat, the strand running the server is about 50% idle. However,
performance
counters suggest that it is executing about 230 million instructions per
second, which,
from my experience thus far, is
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