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From 47f747217811db35854ea06741be3685e8bbd44d Mon Sep 17 00:00:00 2001
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From: Noah Goldstein <goldstein.w.n@gmail.com>
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Date: Mon, 17 Jul 2023 23:14:33 -0500
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Subject: [PATCH] x86: Fix slight bug in `shared_per_thread` cache size
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calculation.
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Content-type: text/plain; charset=UTF-8
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After:
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```
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commit af992e7abdc9049714da76cae1e5e18bc4838fb8
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Author: Noah Goldstein <goldstein.w.n@gmail.com>
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Date: Wed Jun 7 13:18:01 2023 -0500
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x86: Increase `non_temporal_threshold` to roughly `sizeof_L3 / 4`
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```
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Split `shared` (cumulative cache size) from `shared_per_thread` (cache
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size per socket), the `shared_per_thread` *can* be slightly off from
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the previous calculation.
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Previously we added `core` even if `threads_l2` was invalid, and only
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used `threads_l2` to divide `core` if it was present. The changed
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version only included `core` if `threads_l2` was valid.
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This change restores the old behavior if `threads_l2` is invalid by
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adding the entire value of `core`.
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Reviewed-by: DJ Delorie <dj@redhat.com>
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---
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sysdeps/x86/dl-cacheinfo.h | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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[DJ - ported to C8S]
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diff -rup b1/sysdeps/x86/cacheinfo.h b2/sysdeps/x86/cacheinfo.h
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--- b1/sysdeps/x86/cacheinfo.h 2023-08-08 13:44:55.185333601 -0400
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+++ b2/sysdeps/x86/cacheinfo.h 2023-08-08 13:55:16.474680016 -0400
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@@ -253,8 +253,8 @@ get_common_cache_info (long int *shared_
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/* Account for non-inclusive L2 and L3 caches. */
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if (!inclusive_cache)
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{
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- if (threads_l2 > 0)
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- shared_per_thread += core / threads_l2;
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+ long int core_per_thread = threads_l2 > 0 ? (core / threads_l2) : core;
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+ shared_per_thread += core_per_thread;
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shared += core;
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}
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