Just some quick numbers. LPC3250 running at 208 MHz, 64MB RAM, 512MB FLASH.
Case #1: Disable the RTEMS callout timer in LIBBSD (kern_timeout.c) IDLE Task CPUUSE: 99.430% TIME Task CPUUSE: <0.001% Case #2: Enable the RTEMS callout timer but do not call "callout_process()" (the timer service routine just resets the timer and quits) . IDLE Task CPUUSE: 93.144% TIME Task CPUUSE: 6.282% So just processing the 1 tick RTEMS timer in LIBBSD's kern_timeout.c takes up 6% of the CPU processing time. Case #3: Normal callout processing IDLE Task CPUUSE: 87.116% TIME Task CPUUSE: 12.672% Below are the callout functions that are being executed. The number beside each function is the average number of clocks it took to execute (13MHz base clock). ipport_tick - 370/28us pffasttimo - 930/72us pfslowtimo - 5600/431us lpe_tick - 4200/323us _bsd_nd6_timer - 650/50us usb_power_wdog - 1000/80us ohci_rhsc_enable - 400/31us Kevin Kirspel Electrical Engineer - Sr. Staff Idexx Roswell 235 Hembree Park Drive Roswell GA 30076 Tel: (770)-510-4444 ext. 81642 Direct: (770)-688-1642 Fax: (770)-510-4445 -----Original Message----- From: devel [mailto:devel-boun...@rtems.org] On Behalf Of Sebastian Huber Sent: Friday, June 30, 2017 1:15 AM To: devel@rtems.org Subject: Re: LIBBSD On 29/06/17 20:02, Kirspel, Kevin wrote: > For those who run a RTEMS 4.12 single processor application with > LIBBSD, what percentage of time does your application spend in the > timer server task? My NXP LPC3250 application spends about 13% of the > processor time processing the timer server. Most of that time is > spent processing LIBBSD's kernel callouts. I am wondering if there is > an advantage to only call the FreeBSD's callout_process() function > when we know a callout needs to be processed. This would reduce the > number of RTEMS timer fires (which currently fire every tick). Normally, the timer server should be in the range of 0.x% of CPU time. If you have 13%, then you have a lot of timeout processing. What is the reason for this? -- Sebastian Huber, embedded brains GmbH Address : Dornierstr. 4, D-82178 Puchheim, Germany Phone : +49 89 189 47 41-16 Fax : +49 89 189 47 41-09 E-Mail : sebastian.hu...@embedded-brains.de PGP : Public key available on request. Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG. _______________________________________________ devel mailing list devel@rtems.org https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.rtems.org_mailman_listinfo_devel&d=DwIF-g&c=2do6VJGs3LvEOe4OFFM1bA&r=HDiJ93ANMEQ32G5JGdpyUxbdebuwKHBbeiHMr3RbR74&m=wi6q2gTnD-FidfbEqMhvlESvqYn-Fmg-tXnNg62S3BY&s=8pSzson7fylkfTRzYKIMlQnFgvwpY8lpExFHqEEapbc&e= _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
