From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.technolabs.it (host20-155-static.82-213-b.business.telecomitalia.it [213.82.155.20]) by ozlabs.org (Postfix) with ESMTP id 06E72DDECB for ; Sat, 19 Jan 2008 09:34:01 +1100 (EST) MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C85A22.38341666" Subject: ping 127.0.0.1 takes too much Date: Fri, 18 Jan 2008 23:33:59 +0100 Message-ID: From: "DI BACCO ANTONIO - technolabs" To: List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is a multi-part message in MIME format. ------_=_NextPart_001_01C85A22.38341666 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I have two different boards: one with MPC875 running at 66 MHz cpu/66 = MHz bus, one with MPC880 running at 132 MHz cpu /66MHz bus, I load the = same kernel and root file system on both the boards that have only = different u-boot(s). If I do a ping 127.0.0.1 on the MPC875 I get a round trip of 0.300 ms, = while on the other one I get 0.900 ms, I expected the opposite. Could be an issue with memory configuration? In the formula to calculate = the PTx on the MPC885RM manual I used 66 MHz as "system clock" for the = first board and 132 MHz for the second board. Probably this is a mistake = because "system clock" should be the bus clock but how this can so = adversely affect the ping round trip? Thank you, Antonio. ------_=_NextPart_001_01C85A22.38341666 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ping 127.0.0.1 takes too much

I have two different boards: one with MPC875 running = at 66 MHz cpu/66 MHz bus, one with MPC880 running at 132 MHz cpu /66MHz = bus, I load the same kernel and root file system on both the boards that = have only different u-boot(s).

If I do a ping 127.0.0.1 on the MPC875 I get a round trip of 0.300 ms, = while on the other one I get 0.900 ms, I expected the opposite.

Could be an issue with memory configuration? In the formula to calculate = the PTx on the MPC885RM manual I used 66 MHz as "system clock" = for the first board and 132 MHz for the second board. Probably this is a = mistake because "system clock" should be the bus clock but how = this can so adversely affect the ping round trip?

Thank you,
Antonio.

------_=_NextPart_001_01C85A22.38341666-- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from az33egw01.freescale.net (az33egw01.freescale.net [192.88.158.102]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "az33egw01.freescale.net", Issuer "Thawte Premium Server CA" (verified OK)) by ozlabs.org (Postfix) with ESMTP id 70651DDE9E for ; Sat, 19 Jan 2008 09:48:36 +1100 (EST) Message-ID: <47912CDA.9020603@freescale.com> Date: Fri, 18 Jan 2008 16:48:58 -0600 From: Scott Wood MIME-Version: 1.0 To: DI BACCO ANTONIO - technolabs Subject: Re: ping 127.0.0.1 takes too much References: In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Cc: linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , DI BACCO ANTONIO - technolabs wrote: > I have two different boards: one with MPC875 running at 66 MHz cpu/66 > MHz bus, one with MPC880 running at 132 MHz cpu /66MHz bus, I load the > same kernel and root file system on both the boards that have only > different u-boot(s). > > If I do a ping 127.0.0.1 on the MPC875 I get a round trip of 0.300 ms, > while on the other one I get 0.900 ms, I expected the opposite. > > Could be an issue with memory configuration? In the formula to calculate > the PTx on the MPC885RM manual I used 66 MHz as "system clock" for the > first board and 132 MHz for the second board. Probably this is a mistake > because "system clock" should be the bus clock but how this can so > adversely affect the ping round trip? Are you sure the timebase clock is what the kernel thinks it is? Does the time-of-day clock progress at the correct rate? -Scott From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.technolabs.it (host20-155-static.82-213-b.business.telecomitalia.it [213.82.155.20]) by ozlabs.org (Postfix) with ESMTP id D4DD4DDEEB for ; Sat, 19 Jan 2008 10:12:35 +1100 (EST) MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C85A27.9B7FE8CE" Subject: RE: ping 127.0.0.1 takes too much Date: Sat, 19 Jan 2008 00:10:53 +0100 Message-ID: References: <47912CDA.9020603@freescale.com> From: "DI BACCO ANTONIO - technolabs" To: "Scott Wood" Cc: linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is a multi-part message in MIME format. ------_=_NextPart_001_01C85A27.9B7FE8CE Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable >Are you sure the timebase clock is what the kernel thinks it is? Does=20 >the time-of-day clock progress at the correct rate? The kernel receives the CPU clock from the bdinfo structure and thus I = think the kernel knows how fast the CPU is.=20 Bye, Antonio. ------_=_NextPart_001_01C85A27.9B7FE8CE Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RE: ping 127.0.0.1 takes too much

>Are you sure the timebase clock is what the kernel = thinks it is?  Does
>the time-of-day clock progress at the correct rate?

The kernel receives the CPU clock from the bdinfo structure and thus I = think the kernel knows how fast the CPU is.

Bye,
Antonio.

------_=_NextPart_001_01C85A27.9B7FE8CE-- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from az33egw02.freescale.net (az33egw02.freescale.net [192.88.158.103]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "az33egw02.freescale.net", Issuer "Thawte Premium Server CA" (verified OK)) by ozlabs.org (Postfix) with ESMTP id 042B0DDE3E for ; Sat, 19 Jan 2008 10:16:53 +1100 (EST) Message-ID: <47913371.3040908@freescale.com> Date: Fri, 18 Jan 2008 17:17:05 -0600 From: Scott Wood MIME-Version: 1.0 To: DI BACCO ANTONIO - technolabs Subject: Re: ping 127.0.0.1 takes too much References: <47912CDA.9020603@freescale.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Cc: linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , DI BACCO ANTONIO - technolabs wrote: > > >Are you sure the timebase clock is what the kernel thinks it is? Does > >the time-of-day clock progress at the correct rate? > > The kernel receives the CPU clock from the bdinfo structure and thus I > think the kernel knows how fast the CPU is. That wasn't what I asked. I asked whether you checked whether it was actually correct or not. I've seen it be wrong quite often. -Scott