Date: Fri, 19 Jun 2009 01:47:46 GMT From: Yuri <yuri@tsoft.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/135823: 'top' shows wrong CPU usage for multithreaded applications Message-ID: <200906190147.n5J1lkcN053428@www.freebsd.org> Resent-Message-ID: <200906190150.n5J1o1Ni021299@freefall.freebsd.org>
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>Number: 135823 >Category: kern >Synopsis: 'top' shows wrong CPU usage for multithreaded applications >Confidential: no >Severity: serious >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Fri Jun 19 01:50:01 UTC 2009 >Closed-Date: >Last-Modified: >Originator: Yuri >Release: 72-STABLE >Organization: n/a >Environment: >Description: I ran the program with 1500 threads and in top it looked the this: > > PID USERNAME THR PRI NICE SIZE RES STATE C TIME CPU COMMAND > 20382 yuri 1500 99 0 641M 462M umtxn 0 0:00 19623.14% quicksort > <skipped further> > I discussed this in freebsd-hackers@ and got this response from Dan Nelson: <quote> Top doesn't seem to show the right %CPU at all for threaded apps unless you hit H to view each thread individually. Then you get accurate numbers (but you have to manually sum up the threads usage if you want to see the total %CPU for an entire process). </quote> This is a serious bug preventing user to see the very basic property of the running processes. >How-To-Repeat: >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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