Messages in this thread | | | Date | Sun, 9 Mar 2003 19:07:36 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [Bug 350] New: i386 context switch very slow compared to 2.4 due to wrmsr (performance) |
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Ok Jamie, since you've been interested in the past, I thought I'd ask you to test the current context switch stuff. Andi cleaned up some FPU reload stuff (and I fixed a bug in it, tssk tssk Andi - you'd obviously not actually timed your cleanups), and I just committed and pushed out my "cache the value of SYSENTER_CS in the TSS" patch.
It won't bring context switching back to where it _could_ be, but it should be noticeably better. My pipe bandwidth is up from under 600MB/s to about ~700MB/s according to lmbench.
Your SYSENTER_ESP hack would probably get back the rest, but I haven't seen any patches for it, hint hint.
In the meantime, we're almost back to where we were _and_ we support sysenter (ie my system calls are down by almost a factor of four). So we're doing pretty well.
Linus
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