Moblog

This patch implements software receive side packet steering (RPS). RPS distributes the load of received packet processing across multiple CPUs. Problem statement: Protocol processing done in the NAPI context for received packets is serialized per device queue and becomes a bottleneck under high packet load. This substantially limits pps that can be achieved on a single queue NIC and provides no scaling with multiple cores. (lwn.net: Software receive packet steering)

                CPU0       CPU1       CPU2       CPU3
      HI:          0          0          0          0
   TIMER:  480622794  476948579  460999919  467641124
  NET_TX:   25311134   27075847   27513332   27307975     <-----
  NET_RX: 1388399338 4191697027 1491556667  627387845     <-----
   BLOCK:    4632803          3     315726         29
BLOCK_IOPOLL:          0          0          0          0
 TASKLET:         21          4          8          2
   SCHED:  154913375  158601463   97907175  200790209
 HRTIMER:    1576760    2361409    1330088    1545921
     RCU:  421549961  407634645  405460584  415147363

# cat /sys/class/net/eth0/queues/rx-0/rps_cpus
00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,
00000000,00000000,00000000,00000000,00000000,00000000,00000000

# echo f > /sys/class/net/eth0/queues/rx-0/rps_cpus
# cat /sys/class/net/eth0/queues/rx-0/rps_cpus
00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,
00000000,00000000,00000000,00000000,00000000,00000000,0000000f

Moncure Conway, in whose honour we are assembled to-day, devoted his life to two great objects: freedom of thought and freedom of the individual. In regard to both these objects, something has been gained since his time, but something also has been lost. New dangers, somewhat different in form from those of past ages, threaten both kinds of freedom, and unless a vigorous and vigilant public opinion can be aroused in defence of them, there will be much less of both a hundred years hence than there is now. My purpose in this address is to emphasize the new dangers and to consider how they can be met.

Let us begin by trying to be clear as to what we mean by "free thought." This expression has two senses. In its narrower sense it means thought which does not accept the dogmas of traditional religion. In this sense a man is a "free thinker" if he is not a Christian or a Mussulman or a Buddhist or a Shintoist or a member of any of the other bodies of men who accept some inherited orthodoxy. In Christian countries a man is called a " free thinker " if he does not decidedly believe in God, though this would not suffice to make a man a "free thinker" in a Buddhist country.

I do not wish to minimize the importance of free thought in this sense. (...) But there is also a wider sense of "free thought," which I regard as of still greater importance. Indeed, the harm done by traditional religions seems chiefly traceable to the fact that they have prevented free thought in this wider sense. The wider sense is not so easy to define as the narrower, and it will be well to spend some little time in trying to arrive at its essence.

When we speak of anything as "free," our meaning is not definite unless we can say what it is free from. Whatever or whoever is "free" is not subject to some external compulsion, and to be precise we ought to say what this kind of compulsion is. Thus thought is "free" when it is free from certain kinds of outward control which are often present. Some of these kinds of control which must be absent if thought is to be "free" are obvious, but others are more subtle and elusive.

To begin with the most obvious. Thought is not "free" when legal penalties are incurred by the holding or not holding of certain opinions, or by giving expression to one's belief or lack of belief on certain matters. Very few countries in the world have as yet even this elementary kind of freedom. In England, under the Blasphemy Laws, it is illegal to express disbelief in the Christian religion, though in practice the law is not set in motion against the well-to-do. It is also illegal to teach what Christ taught on the subject of non-resistance. Therefore, whoever wishes to avoid becoming a criminal must profess to agree with Christ's teaching, but must avoid saying what that teaching was. In America no one can enter the country without first solemnly declaring that he disbelieves in anarchism and polygamy ; and, once inside, he must also disbelieve in communism. In Japan it is illegal to express disbelief in the divinity of the Mikado. It will thus be seen that a voyage round the world is a perilous adventure. A Mohammedan, a Tolstoyan, a Bolshevik, or a Christian cannot undertake it without at some point becoming a criminal, or holding his tongue about what he considers important truths. This, of course, applies only to steerage passengers ; saloon passengers are allowed to believe whatever they please, provided they avoid offensive obtrusiveness.

It is clear that the most elementary condition, if thought is to be free, is the absence of legal penalties for the expression of opinions. No great country has yet reached to this level, although most of them think they have. The opinions which are still persecuted strike the majority as so monstrous and immoral that the general principle of toleration cannot be held to apply to them.

Legal penalties are, however, in the modern world, the least of the obstacles to freedom of thought. The two great obstacles are economic penalties and distortion of evidence. It is clear that thought is not free if the profession of certain opinions makes it impossible to earn a living. It is clear also that thought is not free if all the arguments on one side of a con- troversy are perpetually presented as attractively as possible, while the arguments on the other side can only be discovered by diligent search. Both these obstacles exist in every large country known to me, except China, which is the last refuge of freedom. It is these obstacles with which I shall be concerned - their present magnitude, the likelihood of their increase, and the possibility of their diminution.

The great majority of men and women, in ordinary times, pass through life without ever contemplating or criticizing, as a whole, either their own conditions or those of the world at large. They find themselves born into a certain place in society, and they accept what each day brings forth, without any effort of thought beyond what the immediate present requires. Almost as instinctively as the beasts of the field, they seek the satisfaction of the needs of the moment, without much forethought, and without considering that by sufficient effort the whole conditions of their lives could be changed. A certain percentage, guided by personal ambition, make the effort of thought and will which is necessary to place themselves among the more fortunate members of the community ; but very few among these are seriously concerned to secure for all the advantages which they seek for themselves. It is only a few rare and exceptional men who have that kind of love towards mankind at large that makes them unable to endure patiently the general mass of evil and suffering, regardless of any relation it may have to their own lives. These few, driven by sympathetic pain, will seek, first in thought and then in action, for some way of escape, some new system of society by which life may become richer, more full of joy and less full of preventable evils than it is at present. But in the past such men have, as a rule, failed to interest the very victims of the injustices which they wished to remedy. The more unfortunate sections of the population have been ignorant, apathetic from excess of toil and weariness, timorous through the imminent danger of immediate punishment by the holders of power, and morally unreliable owing to the loss of self-respect resulting from their degradation. To create among such classes any conscious, deliberate effort after general ameliora- tion might have seemed a hopeless task, and indeed in the past it has generally proved so. But the modern world, by the increase of education and the rise in the standard of comfort among wage-earners, has produced new conditions, more favourable than ever before to the demand for radical reconstruction.