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authorArtyom Tarasenko <atar4qemu@gmail.com>2019-04-12 23:06:17 +0200
committerDavid Gibson <david@gibson.dropbear.id.au>2019-04-26 11:37:57 +1000
commitaaef873b130f4f9c78f8e97b69c235c81b8b8b88 (patch)
treea109020b7eee2bbc95cad4c873bab2f52ee5e40b
parent6e8a65abbbd47a870ddc37484e7c9f183b7a7cce (diff)
downloadfocaccia-qemu-aaef873b130f4f9c78f8e97b69c235c81b8b8b88.tar.gz
focaccia-qemu-aaef873b130f4f9c78f8e97b69c235c81b8b8b88.zip
target/ppc: improve performance of large BAT invalidations
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 <atar4qemu@gmail.com>
Message-Id: <1555103178-21894-4-git-send-email-atar4qemu@gmail.com>
Reviewed-by: Hervé Poussineau <hpoussin@reactos.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
-rw-r--r--target/ppc/mmu_helper.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/target/ppc/mmu_helper.c b/target/ppc/mmu_helper.c
index d226b35739..1dbc9acb75 100644
--- a/target/ppc/mmu_helper.c
+++ b/target/ppc/mmu_helper.c
@@ -1820,6 +1820,13 @@ 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) {