On 2018-09-23 11:20 AM, John David Anglin wrote:
I added a couple of information messages which I have left to help with
diagnosis if the problem should appear on another machine.
Looking at the calculated TLB flush thresholds, I see there is a large
range of numbers. The
most surprising numbers are for panama:
[ 1.246425] Whole TLB flush 5982 cycles, Range flush 18874368 bytes
16515332 cycles
[ 1.246680] Calculated TLB flush threshold 8 KiB
[ 1.247120] TLB flush threshold set to 512 KiB
I don't know whether to believe the numbers or not. But the whole cache
flush seems to
be amazingly fast compared to 4-way machines. On the other hand, the
range flush takes
4.25 times more cycles per byte than phantom.
Here are the numbers for phantom:
[ 6.512604] Whole TLB flush 61861 cycles, Range flush 18874368 bytes
3876885 cycles
[ 6.616030] Calculated TLB flush threshold 1180 KiB
[ 6.680018] TLB flush threshold set to 1180 KiB
Both machines are PA8900 (Shortfin). Panama is 800 MHz and phantom 1000
MHz.
Both have:
[ 0.000000] Kernel default page size is 4 KB. Huge pages enabled with
1 MB physical and 2 MB virtual size.
It would appear the minimum TLB flush threshold needs to be reduced for
machines like panama.
Dave
--
John David Anglin dave.anglin@xxxxxxxx
