4 ms·
I have to agree with moru here. The latency on memory access will be negligible with respect to the latency of any io operations, even within the same data cent
by mmf 12y ago
I have to agree with moru here. The latency on memory access will be negligible with respect to the latency of any io operations, even within the same data center. In my experience anything that involves the OS is >> 1us.
Also beware of anything that declares 10x performance improvement.
- deadgrey19 12y agoYou are assuming that a high performance, latency tuned system is using the OS network stack. This would be a petty naive implementation. Offerings from Solarfalre (OpenOnload) and Exablaze (ExaSock) transparently offload and bypass the kernel stack. Quoted performance numbers are around 1us, of which 500ns is spent getting up and down the PCIE bus. Offloading to the nic makes a whole lot of sense in this space except that it has already been done, and with more compelling perfomance. The authors compleltly failed to take into account existing work.
- moru0011 12y agonope RTT even for these kind of network hardware is >=10 microseconds (I deal with such stuff professionally). Still a big gain going async :-)
- deleted 12y ago[deleted]
- deadgrey19 12y agoSurprising. >10us sounds pretty slow to me.
- moru0011 12y agoround trip. one way 5 to 7 micros. some special cards go down to 3 one way, however with rtt, software usually adds some 2 micros overall
- deadgrey19 12y agoLess than 1us, RTT to software (http://exablaze.com/exanic-x4 http://exablaze.com/exanic-x4) Less than 400ns per switch hop (http://www.arista.com/en/products/7150-series http://www.arista.com/en/products/7150-series) excluding congestion.