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Re: [Discuss-gnuradio] FIFO latency
From: |
Alexander Chemeris |
Subject: |
Re: [Discuss-gnuradio] FIFO latency |
Date: |
Sat, 28 May 2011 22:42:28 +0400 |
On Sat, May 28, 2011 at 22:06, Marcus D. Leech <address@hidden> wrote:
> I evaluated latency of a FIFO (actually an ordinary pipe, but the kernel
> mechanisms are identical), and measured 30usecs average on my
> 1.2GHz AMD Phenom system with plenty 'o memory.
>
> I sent timestamps across the FIFO (struct timeval), and the reader grabbed
> the local time of day, and computed the difference. There's
> a fair amount of uncertainty on the reader due to gettimeofday() call
> overhead. But 30usec on a wimpy CPU is certainly comfortably
> below 1msec.
gettimeofday() is a fast function. But if you want real high-fidelity
- read CPU clock counter. Just make sure your app runs on a one
selected core.
Could you post your app and raw results? I'm interested in
min/mean/max values and distribution graphs. Because max values do
play role when playing with real-time.
--
Regards,
Alexander Chemeris.
- [Discuss-gnuradio] FIFO latency, Marcus D. Leech, 2011/05/28
- Re: [Discuss-gnuradio] FIFO latency,
Alexander Chemeris <=
- Re: [Discuss-gnuradio] FIFO latency, Marcus D. Leech, 2011/05/28
- Re: [Discuss-gnuradio] FIFO latency, Alexander Chemeris, 2011/05/28
- Re: [Discuss-gnuradio] FIFO latency, Alexander Chemeris, 2011/05/28
- Re: [Discuss-gnuradio] FIFO latency, Marcus D. Leech, 2011/05/28
- Re: [Discuss-gnuradio] FIFO latency, Alexander Chemeris, 2011/05/29
- Re: [Discuss-gnuradio] FIFO latency, Colby Boyer, 2011/05/29
- Re: [Discuss-gnuradio] FIFO latency, Alexander Chemeris, 2011/05/30
- Re: [Discuss-gnuradio] FIFO latency, Andre Puschmann, 2011/05/30
- Re: [Discuss-gnuradio] FIFO latency, Alexander Chemeris, 2011/05/30
- Re: [Discuss-gnuradio] FIFO latency, Marcus D. Leech, 2011/05/30