Date: Mon, 31 Jan 2005 11:21:50 +0100 From: Poul-Henning Kamp <phk@phk.freebsd.dk> To: current@freebsd.org Subject: network performance, a low-level measurement Message-ID: <88175.1107166910@critter.freebsd.dk>
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In case anybody can use this for anything: Setup: o Soekris NET4501 (133Mhz AMD Elan CPU) o -Current o stripped down kernel. o no SMP, no WITNESS, no DIAGNOSTIC o unshared interrupt line o if_sis driver modified to FAST intr which just schedules the existing sis_intr on taskqueue_fast o single-user mode o A back-to-back cable to another machine. o A single default sized ping packet Time [uSec] Where ----------------------------------------------------------------------- 000.000 HW-intr start 011.600 HW-intr stop 067.200 Enter sis_intr_task() 074.000 Enter sis_rxeof() 134.800 Enter ifp->if_input() 552.800 Enter sis_startl() 595.600 Exit sis_startl() 753.200 Return from ifp->if_input() 758.000 Exit sis_rxeof() 761.200 Enter sis_txeof() 796.400 Exit sis_txeof() 800.200 Exit sis_intr_task() ----------------------------------------------------------------------- Driver Other [uSec] [uSec] ------------------------------------------------------- HW-intr duration: 11.600 Taskqueue_fast Latency: 55.600 sis_rxeof() duration: 65.500 ifp->if_input() duration: 575.700 sis_startl() duration: 42.800 sis_txeof() duration: 35.200 sis_intr_task duration: 13.800 ------------------------------------------------------- Total 168.900 631.300 ======================================================= Summary: 21% of the time spent in the driver. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
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