[PATCH -v3 0/3] x86, AMD: Correct F15h IC aliasing issue

From: Borislav Petkov
Date: Thu Aug 04 2011 - 10:59:01 EST


From: Borislav Petkov <borislav.petkov@xxxxxxx>

Hi,

here's an updated and revised patchset addressing all comments from last
time:

* saturate bits [14:12] instead of clearing them
* calculate the mask from the CPUID 0x8000_0005 IC identifier instead of
hardcoding it

Please take a look and apply, if no objections.

Thanks.

---
Changelog:

v2:
here's the second version of this patch which actually turned into a
small patchset. As Ingo suggested, the initial patch stays first to ease
backporting and the following 3 patches address (hopefully) all review
comments from the initial submission. The patchset has been tested with
Debian's old stable lenny (i.e. 5.0) distro in a 32-bit environment and
all worked as expected.

Below some performance data to show that there is no noticeable
performance degradation introduced by the changeset.

So please, do take a look again and let me know.

Thanks.

VA alignment enabled.
====================

Performance counter stats for './build.sh' (10 runs):

3187047.935990 task-clock # 24.001 CPUs utilized ( +- 1.37% )
510,888 context-switches # 0.000 M/sec ( +- 0.44% )
60,712 CPU-migrations # 0.000 M/sec ( +- 0.51% )
26,046,891 page-faults # 0.008 M/sec ( +- 0.00% )
1,841,068,123,735 cycles # 0.578 GHz ( +- 1.10% ) [63.39%]
560,044,437,348 stalled-cycles-frontend # 30.42% frontend cycles idle ( +- 1.13% ) [64.65%]
436,165,228,465 stalled-cycles-backend # 23.69% backend cycles idle ( +- 1.19% ) [67.21%]
1,461,854,088,667 instructions # 0.79 insns per cycle
# 0.38 stalled cycles per insn ( +- 0.77% ) [70.31%]
334,169,452,362 branches # 104.852 M/sec ( +- 1.20% ) [69.43%]
21,485,007,982 branch-misses # 6.43% of all branches ( +- 0.68% ) [65.01%]

132.787483539 seconds time elapsed ( +- 1.37% )


VA alignment disabled
=====================

Performance counter stats for './build.sh' (10 runs):

3173688.887193 task-clock # 24.001 CPUs utilized ( +- 1.37% )
511,425 context-switches # 0.000 M/sec ( +- 0.28% )
60,522 CPU-migrations # 0.000 M/sec ( +- 0.60% )
26,046,902 page-faults # 0.008 M/sec ( +- 0.00% )
1,832,825,813,094 cycles # 0.578 GHz ( +- 0.96% ) [63.60%]
563,123,451,900 stalled-cycles-frontend # 30.72% frontend cycles idle ( +- 0.96% ) [63.97%]
439,565,070,106 stalled-cycles-backend # 23.98% backend cycles idle ( +- 1.23% ) [66.69%]
1,465,314,643,020 instructions # 0.80 insns per cycle
# 0.38 stalled cycles per insn ( +- 0.74% ) [70.11%]
332,416,669,982 branches # 104.741 M/sec ( +- 0.85% ) [69.71%]
21,181,821,204 branch-misses # 6.37% of all branches ( +- 0.97% ) [65.93%]

132.230903628 seconds time elapsed ( +- 1.37% )

stock 3.0
=========

Performance counter stats for './build.sh' (10 runs):

3369707.240439 task-clock # 24.001 CPUs utilized ( +- 1.18% )
510,450 context-switches # 0.000 M/sec ( +- 0.29% )
58,906 CPU-migrations # 0.000 M/sec ( +- 0.35% )
26,057,272 page-faults # 0.008 M/sec ( +- 0.00% )
1,836,326,075,063 cycles # 0.545 GHz ( +- 1.05% ) [63.51%]
561,850,647,545 stalled-cycles-frontend # 30.60% frontend cycles idle ( +- 1.03% ) [64.17%]
439,923,021,200 stalled-cycles-backend # 23.96% backend cycles idle ( +- 1.10% ) [66.64%]
1,467,236,934,265 instructions # 0.80 insns per cycle
# 0.38 stalled cycles per insn ( +- 0.87% ) [70.06%]
331,937,054,120 branches # 98.506 M/sec ( +- 0.81% ) [69.83%]
21,228,553,080 branch-misses # 6.40% of all branches ( +- 0.87% ) [65.79%]

140.398317711 seconds time elapsed ( +- 1.18% )


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