sata_sil24: configure max read request size to 4k
Due to request posting limitations, bandwidth of sil3132 is limited to
around 120MB/s with the minimum pci-e payload size (128bytes) which is
used by most consumer systems. However, write throughput can be
slightly (~3%) increased by increasing the max read requeset size.
Configure it to 4k which is the maximum supported. This optimization
is also done by SIMG's windows driver.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index 4621807..ccee930 100644
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -1329,6 +1329,11 @@
}
}
+ /* Set max read request size to 4096. This slightly increases
+ * write throughput for pci-e variants.
+ */
+ pcie_set_readrq(pdev, 4096);
+
sil24_init_controller(host);
pci_set_master(pdev);