Messages in this thread | | | From | "Felipe Alfaro Solana" <> | Date | Sun, 02 Mar 2003 12:40:35 +0100 | Subject | Re: anticipatory scheduling questions |
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----- Original Message ----- From: Andrew Morton <akpm@digeo.com> Date: Sat, 1 Mar 2003 02:40:24 -0800 To: "Felipe Alfaro Solana" <felipe_alfaro@linuxmail.org> Subject: Re: anticipatory scheduling questions > "Felipe Alfaro Solana" <felipe_alfaro@linuxmail.org> wrote: > > > > ----- Original Message ----- > > > Does basic 2.5.63 do the same thing? Do you have a feel > > > for when it started happening? > > > > This has happened since the moment I switched from > > 2.4 to 2.5.63-mm1. > > You have not actually said whether 2.5.63 base exhibits > the same problem. From the vmstat traces it appears > that the answer is "yes"? Both 2.5.63 and 2.5.63-mm1 exhibit this behavior, but can't be reproduced with 2.4.20-2.54. > > I have retested this with 2.4.20-2.54, 2.5.63 and 2.5.63-mm1... > > and have attached the files to this message > > Thanks. Note how 2.4 is consuming a few percent CPU, whereas 2.5 is > consuming 100%. Approximately half of it system time. It seems is not "user" or "system" time what's being consumed, it's "iowait" Look below :-) > It does appear that some change in 2.5 has caused evolution to go berserk > during this operation. I wouldn't say it's exactly Evolution what's going berserk. Doing a "top -s1" while trying to reply to a big e-mail message, I've noticed that "top" reports "iowait" starting at ~50%, then going up very fast and then staying up at 90-95% all the time. This happens on 2.5.63 and 2.5.63-mm1, however, on 2.4.20-2.54 kernel, "iowait" stays all the time exactly at "0%" and idle time remains steady at 90-95%. These measures were taken using "top" with a delay of 1 second, starting at the moment in which I try replying to a large e-mail message. > The next step please is: > > a) run top during the operation, work out which process is chewing all > that CPU. Presumably it will be evolution or aspell Well, the "top" command reveals that Evolution is taking very little CPU usage (between 1 and 6%). Nearly all the time is accounted under "iowait". The other Evolution processes top at a peak sum of 5% of CPU usage, more or less. > b) Do it again and this time run > strace -p $(pidof evolution) # or aspell I think this is going to be difficult... as I said Evolution is a very complex program and it spawns a lot of processes. When I click the Reply, Evolution spawns two processes: "gnome-gtkhtml-editor" and "gnome-spell-component". I have little experience with process tracing and don't know how to attach to those processes from the very beginning. Attaching to the main Evolution process doesn't help: the "strace" command dumps a lot of info when Evolution starts up, but starts being useless at the moment I click the Reply and Evolution spawns these two new processes to process the request. Any ideas? > This will tell us what it is up to. I'm sorry I can't help much more. Can you give me more pointers on how to nail this down? Thanks! Felipe Alfaro Solana -- ______________________________________________ http://www.linuxmail.org/ Now with e-mail forwarding for only US$5.95/yr
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