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[Qemu-devel] [PATCH 3/4] target/ppc: improve performance of large BAT in
From: |
Artyom Tarasenko |
Subject: |
[Qemu-devel] [PATCH 3/4] target/ppc: improve performance of large BAT invalidations |
Date: |
Fri, 12 Apr 2019 23:06:17 +0200 |
Performing a complete flush is ~ 100 times faster than flushing
256MiB of 4KiB pages. Set a limit of 1024 pages and perform a complete
flush afterwards.
This patch significantly speeds up AIX 5.1 and NetBSD-ofppc.
Signed-off-by: Artyom Tarasenko <address@hidden>
---
target/ppc/mmu_helper.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/target/ppc/mmu_helper.c b/target/ppc/mmu_helper.c
index 4a6be4d..d7eed3a 100644
--- a/target/ppc/mmu_helper.c
+++ b/target/ppc/mmu_helper.c
@@ -1809,6 +1809,13 @@ static inline void do_invalidate_BAT(CPUPPCState *env,
target_ulong BATu,
base = BATu & ~0x0001FFFF;
end = base + mask + 0x00020000;
+ if (((end - base) >> TARGET_PAGE_BITS) > 1024) {
+ /* Flushing 1024 4K pages is slower than a complete flush */
+ LOG_BATS("Flush all BATs\n");
+ tlb_flush(CPU(cs));
+ LOG_BATS("Flush done\n");
+ return;
+ }
LOG_BATS("Flush BAT from " TARGET_FMT_lx " to " TARGET_FMT_lx " ("
TARGET_FMT_lx ")\n", base, end, mask);
for (page = base; page != end; page += TARGET_PAGE_SIZE) {
--
2.7.2