Date: Wed, 4 Mar 2009 10:28:36 +0200 From: Artyom Mirgorodsky <man@email.com.ua> To: Hans Petter Selasky <hselasky@c2i.net> Cc: freebsd-usb@freebsd.org Subject: Re: Low perfomance when read from usb flash drive Message-ID: <200903041028.37027.man@email.com.ua> In-Reply-To: <200903032243.31914.hselasky@c2i.net> References: <200903010045.44904.man@email.com.ua> <200903032006.54451.man@email.com.ua> <200903032243.31914.hselasky@c2i.net>
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>Repeat the same test using FreeBSD -current. >a) On the machine where it is slow. vmstat -i ; sleep 1 ; vmstat -i interrupt total rate irq1: atkbd0 233 2 irq14: ata0 85 0 irq16: vgapci0 5377 52 irq21: hdac0 ohci0 742 7 irq22: nfe0 ehci0 23610 229 irq23: atapci1 5405 52 cpu0: timer 203959 1980 cpu1: timer 200914 1950 Total 440325 4275 interrupt total rate irq1: atkbd0 234 2 irq14: ata0 85 0 irq16: vgapci0 5439 52 irq21: hdac0 ohci0 742 7 irq22: nfe0 ehci0 24621 236 irq23: atapci1 5405 51 cpu0: timer 205981 1980 cpu1: timer 202937 1951 Total 445444 4283 >I think the reduced performance can be explained by a clamp on the interrupt >rate around 1000 interrupts per second instead of 8000. Maybe someone has an >explanation for this? You right, the interrupt rate around 1000 (1011) on this machine, but on FreeBSD 7.1 more 3000. If it is some kind of interrupt aggregation, may be I can try to turn it off? >b) On the machine where it is fast. vmstat -i ; sleep 1 ; vmstat -i interrupt total rate irq4: uart0 4154 0 irq14: ata0 472922 0 irq15: ata1 26 0 irq18: em0 752711 0 irq21: ahc0 53 0 irq23: ehci0 103456 0 irq24: em1 147 0 cpu0: timer 1551216517 2000 cpu1: timer 1551195251 2000 Total 3103745237 4001 interrupt total rate irq4: uart0 4154 0 irq14: ata0 472923 0 irq15: ata1 26 0 irq18: em0 752713 0 irq21: ahc0 53 0 irq23: ehci0 110949 0 irq24: em1 147 0 cpu0: timer 1551218551 2000 cpu1: timer 1551197285 2000 Total 3103756801 4001
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