When using NSS, only schedule transport socket reads when the transport buffer is empty.

net/base/nss_memio.h

Index: net/base/nss_memio.h
diff --git a/net/base/nss_memio.h b/net/base/nss_memio.h
index 7d889ebcb5ec8200a22a21430d10eb3a5c11eaab..e8db27c64002e04efffbc6c0e6ef79af78f7736f 100644
--- a/net/base/nss_memio.h
+++ b/net/base/nss_memio.h
@@ -50,6 +50,12 @@ void memio_SetPeerName(PRFileDesc *fd, const PRNetAddr *peername);
  */
 memio_Private *memio_GetSecret(PRFileDesc *fd);
 
+/* Ask memio how many bytes were requested by a higher layer during the last
+ * read request that could not be satisfied (due to the buffer being empty).
+ * Returns 0 if there was no unsatisfied read request.
+ */
+int memio_GetReadRequest(memio_Private *secret);

[wtc, 2012/12/20 02:41:22]

The specification of this function is not very clear unless
I look at its implementation in the .c file.

All we need is a boolean function that tells us whether a
read was requested by a higher layer when the buffer was
empty.

[Ryan Sleevi, 2012/12/20 02:55:58]

While yes, we only need a bool, I typed it as an int both to match the OpenSSL
implementation and to allow for the 'proper' behaviour from the point of view of
a generic socket API, which would be to have the transport only read 'as much'
data as requested.

+
 /* Ask memio where to put bytes from the network, and how many it can handle.
  * Returns bytes available to write, or 0 if none available.
  * Puts current buffer position into *buf.