Messages in this thread | | | From | Ian Rogers <> | Date | Thu, 2 Jun 2022 09:59:29 -0700 | Subject | Re: [PATCH v4 00/12] perf c2c: Support display for Arm64 |
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On Wed, Jun 1, 2022 at 3:25 AM Leo Yan <leo.yan@linaro.org> wrote: > > Hi Joe, > > On Tue, May 31, 2022 at 02:44:07PM -0400, Joe Mario wrote: > > [...] > > > Hi Leo: > > I built a new perf with your patches and ran it on a 2-numa node Neoverse platform. > > I then ran my simple test that creates reader and writer threads to tug on the same cacheline. > > The c2c output is appended below. > > > > The output looks good, especially where you've broken out the (average) cycles for local and remote peer loads. > > And I'm glad to see you fixed the "Node" column. I use that a lot to help detect remote node accesses. > > Thanks a lot for your testing and suggestions, which are really helpful! > > > And the "PA cnt" field is working as well, which is important to see if numa_balance is moving the data around. > > Good to know this. To be honest, before I didn't note for "PA cnt" > metric, I checked a bit for the code, this metrics is very useful to > understand how it's severe that a cache line is accessed from different > addresses, so we can get sense how a cache line is hammered. > > > ================================================= > > Shared Data Cache Line Table > > ================================================= > > # > > # ----------- Cacheline ---------- Peer ------- Load Peer ------- Total Total Total --------- Stores -------- ----- Core Load Hit ----- - LLC Load Hit -- - RMT Load Hit -- --- Load Dram ---- > > # Index Address Node PA cnt Snoop Total Local Remote records Loads Stores L1Hit L1Miss N/A FB L1 L2 LclHit LclHitm RmtHit RmtHitm Lcl Rmt > > # ..... .................. .... ...... ....... ....... ....... ....... ....... ....... ....... ....... ....... ....... ....... ....... ....... ........ ....... ........ ....... ........ ........ > > # > > 0 0x422140 0 6904 74.86% 137 131 6 148008 144970 3038 0 0 3038 0 144833 120 11 0 6 0 0 0 > > 1 0xffffd976e63ae5c0 1 6 3.83% 7 7 0 15 15 0 0 0 0 0 8 4 3 0 0 0 0 0 > > 2 0xffff07ffbf290980 0 5 2.19% 4 2 2 14 14 0 0 0 0 0 10 1 1 0 2 0 0 0 > > 3 0xffffd976e57275c0 1 1 0.55% 1 1 0 1 1 0 0 0 0 0 0 1 0 0 0 0 0 0 > > 4 0xffffd976e6071c00 1 3 0.55% 1 0 1 4 4 0 0 0 0 0 3 0 0 0 1 0 0 0 > > [snip] > > ================================================= > > Shared Cache Line Distribution Pareto > > ================================================= > > # > > # -- Peer Snoop -- ------- Store Refs ------ --------- Data address --------- ---------- cycles ---------- Total cpu Shared > > # Num Rmt Lcl L1 Hit L1 Miss N/A Offset Node PA cnt Code address rmt peer lcl peer load records cnt Symbol Object Source:Line Node > > # ..... ....... ....... ....... ....... ....... .................. .... ...... .................. ........ ........ ........ ....... ........ .......................... ....... ......................... .... > > # > > ---------------------------------------------------------------------- > > 0 6 131 0 0 3038 0x422140 > > ---------------------------------------------------------------------- > > 0.00% 0.00% 0.00% 0.00% 52.60% 0x8 0 1 0x400e6c 0 0 0 1598 4 [.] writer tugtest tugtest.c:152 0 1 > > 0.00% 0.00% 0.00% 0.00% 47.40% 0x10 0 1 0x400e7c 0 0 0 1440 4 [.] writer tugtest tugtest.c:153 0 1 > > 33.33% 75.57% 0.00% 0.00% 0.00% 0x20 0 1 0x401018 4095 3803 3419 409 4 [.] reader tugtest tugtest.c:187 0 1 > > 66.67% 24.43% 0.00% 0.00% 0.00% 0x28 0 1 0x401034 4095 3470 3643 413 4 [.] reader tugtest tugtest.c:187 0 1 > > > > ---------------------------------------------------------------------- > > 1 0 7 0 0 0 0xffffd976e63ae5c0 > > ---------------------------------------------------------------------- > > 0.00% 57.14% 0.00% 0.00% 0.00% 0x0 1 1 0xffffd976e4815fbc 0 1333 0 4 2 [k] ktime_get [kernel.kallsyms] seqlock.h:276 1 > > 0.00% 14.29% 0.00% 0.00% 0.00% 0x0 1 1 0xffffd976e4816d10 0 266 794 4 3 [k] ktime_get_update_offsets_n [kernel.kallsyms] seqlock.h:276 0 1 > > 0.00% 28.57% 0.00% 0.00% 0.00% 0x30 1 1 0xffffd976e4816d20 0 87 150 4 3 [k] ktime_get_update_offsets_n [kernel.kallsyms] timekeeping.c:2298 0 1 > > > > ---------------------------------------------------------------------- > > 2 2 2 0 0 0 0xffff07ffbf290980 > > ---------------------------------------------------------------------- > > 50.00% 100.00% 0.00% 0.00% 0.00% 0x4 0 1 0xffffd976e47d2bdc 1217 1600 1147 4 3 [k] queued_spin_lock_slowpath [kernel.kallsyms] qspinlock.c:511 0 1 > > 50.00% 0.00% 0.00% 0.00% 0.00% 0x4 0 1 0xffffd976e47d2a2c 4033 0 0 1 1 [k] queued_spin_lock_slowpath [kernel.kallsyms] qspinlock.c:382 0 1 > > > > ---------------------------------------------------------------------- > > > > Thanks for doing this. It looks good. > > You are welcome! And very appreicate your helping to mature the code. > > > I'll assume someone else is reviewing your code changes. > > Yeah, let's give a bit more time for reviewing. > > Thanks, > Leo
This is great Leo! I've not been able to test the changes but I didn't have any coding comments (happy to give an Acked-by). Do you think we can add a test for this? The test can skip when c2c isn't supported.
Thanks, Ian
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