If your 1 CPU is 95% idle, it can do other "user requests". But not if the other "user requests" require disk I/O, they will also block regardless of which CPU they are using. I think there is a performance problem with your disks. But just a guess. Guy -----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Jason C. Leach Sent: Thursday, July 22, 2004 2:10 PM To: Guy Cc: linux-raid@xxxxxxxxxxxxxxx Subject: Re: I/O Blocking Guy: CPU load is very low (95-96% idle), load avg is 2. The system has 512MB RAM, some free and only a few megs swapped out. If I was really working the RAID card I would get load avgs more like 2.5-3. Right now just light USB and system usage and I am at 2. I though if one CPU was tied up with the process that is blocking (using the RAID card), then the second would be free to deal with user requests. Or am I misunderstanding SMP and blocking I/O? J. Guy wrote: >What is the CPU load like? Are you at 100%? If so a second CPU may help. >If you are blocked on i/o it should not use much CPU, so my guess is your >CPU load is very low, and a second CPU won't do much. How much RAM do you >have? Are you swapping? > >Guy > >-----Original Message----- >From: linux-raid-owner@xxxxxxxxxxxxxxx >[mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Jason C. Leach >Sent: Thursday, July 22, 2004 12:29 PM >To: linux-raid@xxxxxxxxxxxxxxx >Subject: I/O Blocking > >Hi, > >Both the RAID (Promise SuperTrak 6000) or the USB subsystems really >drive the system load up. I'm using a AMD 3200+ system that is only a >few months old with the 2.4.25 kernel. When the I/O systems are >blocking the system is very unresponsive. Some times samba will timeout, >or I'll wait several seconds for commands like df, top, w and so on. > >I am wondering if I were to use a dual CPU system, would this solve my >I/O blocking problem? Would one CPU tend to the I/O subsystem and the >second would deal with other system requests I (samba, DB, LDAP, ...)? >- >To unsubscribe from this list: send the line "unsubscribe linux-raid" in >the body of a message to majordomo@xxxxxxxxxxxxxxx >More majordomo info at http://vger.kernel.org/majordomo-info.html > > > - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
