Date: Mon, 30 Jun 2008 22:28:44 +0400 From: Vladimir Grebenschikov <vova@fbsd.ru> To: David Xu <davidxu@FreeBSD.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, current@FreeBSD.org, cvs-all@FreeBSD.org Subject: [fwd] cvs commit: src/lib/libthr/thread thr_mutex.c thr_umtx.c thr_umtx.h src/sys/kern kern_umtx.c src/sys/sys umtx.h Message-ID: <1214850524.42354.9.camel@localhost> In-Reply-To: <200806240737.m5O7bhc5018813@repoman.freebsd.org> References: <200806240737.m5O7bhc5018813@repoman.freebsd.org>
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On Tue, 2008-06-24 at 07:32 +0000, David Xu wrote:
This commit makes threaded application almost unusable on 8-CURRENT.
Applications eat 100% CPU all the time and works _very_ slowly.
(top shows several threads for every constantly applications eating CPU)
Following applications are affected for me: firefox, evolution, eclipse
(probably more).
Reverting user-land part of commit fixes problem, reverting kernel
changes nothing regarding the problem.
I have:
FreeBSD 8.0-CURRENT #0: Fri Jun 20 17:14:23 MSD 2008
root@vbook.fbsd.ru:/usr/obj/usr/src/sys/VBOOK
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Intel(R) Core(TM)2 CPU T7200 @ 2.00GHz (1995.01-MHz 686-class CPU)
Origin = "GenuineIntel" Id = 0x6f6 Stepping = 6
Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
Features2=0xe3bd<SSE3,RSVD2,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM>
AMD Features=0x20100000<NX,LM>
AMD Features2=0x1<LAHF>
Cores per package: 2
> davidxu 2008-06-24 07:32:12 UTC
>
> FreeBSD src repository
>
> Modified files:
> lib/libthr/thread thr_mutex.c thr_umtx.c thr_umtx.h
> sys/kern kern_umtx.c
> sys/sys umtx.h
> Log:
> SVN rev 179970 on 2008-06-24 07:32:12Z by davidxu
>
> Add two commands to _umtx_op system call to allow a simple mutex to be
> locked and unlocked completely in userland. by locking and unlocking mutex
> in userland, it reduces the total time a mutex is locked by a thread,
> in some application code, a mutex only protects a small piece of code, the
> code's execution time is less than a simple system call, if a lock contention
> happens, however in current implemenation, the lock holder has to extend its
> locking time and enter kernel to unlock it, the change avoids this disadvantage,
> it first sets mutex to free state and then enters kernel and wake one waiter
> up. This improves performance dramatically in some sysbench mutex tests.
>
> Tested by: kris
> Sounds great: jeff
>
> Revision Changes Path
> 1.75 +33 -35 src/lib/libthr/thread/thr_mutex.c
> 1.17 +60 -10 src/lib/libthr/thread/thr_umtx.c
> 1.14 +13 -9 src/lib/libthr/thread/thr_umtx.h
> 1.71 +142 -35 src/sys/kern/kern_umtx.c
> 1.33 +3 -1 src/sys/sys/umtx.h
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--
Vladimir B. Grebenschikov
vova@fbsd.ru
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