On 5/27/20 Paul FLOYD wrote:
Well, no real surprises. This is with a testcase that runs standalone in about
5 seconds and under DHAT in about 200 seconds (so a reasonable slowdown of 40x).
# Overhead Command Shared Object
Symbol
# ... ..
[snip - perf]
Well, no real surprises. This is with a testcase that runs standalone in about
5 seconds and under DHAT in about 200 seconds (so a reasonable slowdown of 40x).
# Overhead Command Shared Object
> So (4 * 5 * 10 * 3) is a slowdown of 600X, which turns 10 minutes into 100
hours.
What I'm seeing is a DHAT-only slowdown that is much more than that.
Running 'perf' is likely to give data and strong hints about what is going on.
The overhead of 'perf' is only a few percent.
perf recor
> Message du 26/05/20 13:19> De : "John Reiser" the ratio is about 1:50. So
> right away, that's a hardware slowdown of 4X.Maybe more. The machine has
> 12Mbyte of cache according to cpuinfo.> Valgrind runs every tool
> single-threaded. So if your app averages 5 active threads,> then that is a
> That doesn't sound right. I use DHAT extensively and expect a slowdown of>
perhaps 50:1, maybe less. What you're describing is a slowdown factor of> at
least several thousand.>> Bear in mind though that (1) V sequentialises thread
execution, which wil> make a big difference if the program is
The server has 48Gbytes of RAM and only about 6Gbytes is being used.
The executable is quite big
text data bss dec hex filename
57369168 417156 20903108 78689432 4b0b498 [snip]
The run under DHAT is using about 2Gbytes virtual and 1.5Gbytes resident
according to htop. Running standalone those
On 5/26/20, Paul FLOYD wrote:
> > I'm running DHAT on what I consider to be a relatively small example.
> > Standalone the executable runs in a bit under 10 minutes. Based on the CPU
> > time that we print after every 10% of
progress, under DHAT the same executable is going to take about 422
That doesn't sound right. I use DHAT extensively and expect a slowdown of
perhaps 50:1, maybe less. What you're describing is a slowdown factor of
at least several thousand.
Bear in mind though that (1) V sequentialises thread execution, which wil
make a big difference if the program is heavil
On 5/26/20, Paul FLOYD wrote:
I'm running DHAT on what I consider to be a relatively small example.
Standalone the executable runs in a bit under 10 minutes. Based on the CPU time
that we print after every 10% of progress, under DHAT the same executable is
going to take about 422 hours - abou
Hi
I'm running DHAT on what I consider to be a relatively small example.
Standalone the executable runs in a bit under 10 minutes. Based on the CPU time
that we print after every 10% of progress, under DHAT the same executable is
going to take about 422 hours - about two and a half weeks.
Do
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