[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] 46% performance drop with change in glibc
Well, I thought I was losing my mind, but hopefully not. When I upgraded glibc on FC3, I did forget to move tls to tls.disabled. So, I moved it to tls.disabled, and the problem goes away. HOWEVER, on FC4, I always had tls moved to tls.disabled, and I am still getting this problem. So, on FC4, why would these libs not be in /lib/tls in the first place? /lib/tls[.disabled] on fc3: i486 i686 libc.so.6 libm.so.6 libpthread.so.0 librt.so.1 libthread_db.so.1 i586 libc-2.3.3.so libm-2.3.3.so libpthread-2.3.3.so librt-2.3.3.so libthread_db-1.0.so /lib/tls[.disabled] on fc4: i486 i586 i686 -Andrew On Wednesday 02 November 2005 13:23, Andrew Theurer wrote: > I had thought I moved tls to tls.disabled, but I'll check again. > > -Andrew > > On Wednesday 02 November 2005 13:17, Kip Macy wrote: > > The segment offset handling emulation is expensive. You need to either > > rename your TLS libraries away or use a glibc with the xen TLS patch. > > > > -Kip > > > > On 11/2/05, Andrew Theurer <habanero@xxxxxxxxxx> wrote: > > > I have been trying to track down a xen performance regression from > > > Fedora core3 to core4 i386 and I think I might have narrowed it down. > > > First some background info: I ran the SDET benchmark [1] and > > > discovered that we have about a 45% regression after upgrading to > > > Fedora core 4. I noticed xenoprofile showed ~20% in error_code on FC4, > > > but only ~3.5% in error_code (should we even have 3%?!?) on FC3. At > > > first I thought the change to gcc-4 might have something to do with > > > it, so I tried gcc4 on FC3 -no regression. I noticed glibc was also > > > different, so I upgraded FC3 from 2.3.3 to 2.3.5 -bingo. I am not sure > > > what about glibc is causing this, but here are the two profiles: > > > > > > fc3 with glic-2.3.3: > > > > > > samples % app name symbol name > > > 56097 22.8770 cc1 (no symbols) > > > 22780 9.2900 troff (no symbols) > > > 8646 3.5259 xen-unstable-syms error_code > > > 7822 3.1899 grotty (no symbols) > > > 5283 2.1545 libc-2.3.3.so <http://libc-2.3.3.so> _int_malloc > > > 4914 2.0040 vmlinux-2.6.12-xen0-up buffered_rmqueue > > > 4453 1.8160 bash (no symbols) > > > 4372 1.7830 xen-unstable-syms get_page_from_l1e > > > 3492 1.4241 xen-unstable-syms put_page_from_l1e > > > 3338 1.3613 vmlinux-2.6.12-xen0-up system_call > > > 3040 1.2397 xen-unstable-syms hypercall > > > 2801 1.1423 xen-unstable-syms alloc_page_type > > > 2799 1.1415 vmlinux-2.6.12-xen0-up zap_pte_range > > > 2798 1.1411 libstdc++.so.6.0.3 (no symbols) > > > 2761 1.1260 libc-2.3.3.so <http://libc-2.3.3.so> vfprintf > > > 2637 1.0754 vmlinux-2.6.12-xen0-up do_no_page > > > 2555 1.0420 libc-2.3.3.so <http://libc-2.3.3.so> > > > __i686.get_pc_thunk.bx 2548 1.0391 vmlinux-2.6.12-xen0-up page_fault > > > > > > fc3 with glibc-2.3.5: > > > > > > samples % app name symbol name > > > 133404 22.7469 xen-unstable-syms error_code > > > 31411 5.3559 libc-2.3.5.so <http://libc-2.3.5.so> malloc > > > 30316 5.1692 troff (no symbols) > > > 20632 3.5180 libc-2.3.5.so <http://libc-2.3.5.so> vfprintf > > > 16626 2.8349 xen-unstable-syms gpf_emulate_4gb > > > 10639 1.8141 xen-unstable-syms do_general_protection > > > 10105 1.7230 grotty (no symbols) > > > 9837 1.6773 libc-2.3.5.so <http://libc-2.3.5.so> getwchar > > > 8057 1.3738 xen-unstable-syms decode_register > > > 7347 1.2527 libc-2.3.5.so <http://libc-2.3.5.so> iswgraph > > > 7114 1.2130 vmlinux-2.6.12-xen0-up buffered_rmqueue > > > 6926 1.1810 cc1 is_attribute_p > > > 6679 1.1388 libc-2.3.5.so <http://libc-2.3.5.so> _int_malloc > > > 6350 1.0827 xen-unstable-syms fixup_seg > > > 5673 0.9673 xen-unstable-syms get_baselimit > > > 5039 0.8592 bash (no symbols) > > > 4957 0.8452 xen-unstable-syms get_page_from_l1e > > > 4908 0.8369 xen-unstable-syms put_page_from_l1e > > > 4576 0.7803 ld-2.3.5.so <http://ld-2.3.5.so> do_lookup_x > > > 4322 0.7370 xen-unstable-syms hypercall > > > 3915 0.6676 vmlinux-2.6.12-xen0-up system_call > > > > > > I assume something related to gpf_emulate_4gb... > > > Anyone have an idea why this would cause such a regression? > > > > > > -Andrew > > > > > > > > > [1] SDET described here: > > > http://www.spec.org/osg/sdm91/ > > > > > > _______________________________________________ > > > Xen-devel mailing list > > > Xen-devel@xxxxxxxxxxxxxxxxxxx > > > http://lists.xensource.com/xen-devel > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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