Step 1 has been taken: this mailing list is archived, so searching for "roach file i/o" will bring this thread up. I don't know about steps 2-inf.
On Wed, Apr 28, 2010 at 8:20 AM, melvyn wright <[email protected]> wrote: > Aaron, Jason, > > Good. > How and where do we document this, so others don't have to bump into it ? > > Mel. > > On 4/28/10, Aaron Parsons <[email protected]> wrote: >> So commenting out all the lines in /etc/syslog.conf and then rebooting >> seems to have done the trick. I now see ~7.8MB/s read times. Yay! >> >> Muchas gracias! >> >> On Wed, Apr 28, 2010 at 8:00 AM, Jason Manley <[email protected]> wrote: >>> Syslog flushes all logs to disk as they happen (synchronous writes). So it >>> is very slow. >>> >>> I believe tcpborphserver (ROACH's KATCP server) should not be logging >>> anything anymore. >>> >>> The logs you're seeing are likely from the kernel itself, as BORPH logs >>> every bus transaction. A kernel recompile is required to remove this >>> entirely. But you can configure what is logged to disk by syslog in >>> /etc/syslog.conf. Perhaps try to disable the logging of these messages. >>> >>> You should be getting around 7MegaBytes/s across that bus. Even over a >>> network. This is just dumping data, and does not count bus overhead >>> incurred >>> by reading small quantities of data from different BRAMs etc. >>> >>> If you try to dump the whole DRAM using tcpborphserver's "bulkread" >>> command, >>> you should achieve something close to 3.5MB/s across the network using the >>> Python KATCP and the wrapper in corr. >>> >>> Jason >>> >>> On 28 Apr 2010, at 08:11, Aaron Parsons wrote: >>> >>>> I'm currently only able to read ~100kB/s from shared BRAMs on the >>>> ROACH. I assume the ROACH can do better than this. >>>> >>>> I've profiled my code and am certain that the bottleneck is in reading >>>> BRAM files. When I looked closer, I found a bunch of logging showing >>>> up in /proc/kmsg for every file transaction. Acting on the theory >>>> that this logging was slowing everything down, I killed syslogd and >>>> klogd (/etc/init.d/klogd stop, etc). Yet I still get lines in >>>> /proc/kmsg from "proc_borph". I can't find any processes that I >>>> recognize as potentiall logging daemons, and I haven't found anything >>>> with lsof that indicates what may be writing to /proc/kmsg. I'm left >>>> thinking that maybe this logging is compiled into the kernel. >>>> >>>> Does anyone know what is cause such lousy file I/O performance on the >>>> ROACH? If it is indeed a problem with excessive logging, how do I >>>> stop it? >>>> >>>> -- >>>> Aaron Parsons >>>> >>>> 510-406-4322 (cell) >>>> Campbell Hall 523, UCB >>>> >>> >>> >> >> >> >> -- >> Aaron Parsons >> >> 510-406-4322 (cell) >> Campbell Hall 523, UCB >> >> > -- Aaron Parsons 510-406-4322 (cell) Campbell Hall 523, UCB
